I guess it's subjective and a matter of perspective.
I'm coming here from the Aegean subforum, since Aegean constitutes about 90% of my flights. However I struck a great deal last minute on Sky Express last week for a flight... yesterday (needed to travel on a very short notice), so having never flown with Sky Express before, I decided it was worth it (besides, I wouldn't be needing the miles with Aegean's ffp, since my next gold year starts in 2 months).

If you just compare the flying experience on the A320 vs the ATR72-600 (which I flew on for the very first time yesterday) I would say on a 1h flight (in my case Athens to Corfu) it barely makes any noticeable difference. The atr is slower and the exhaust gases make a blur out of whatever it is you're looking at through the window, but the seats are actually more spacious on the atr!

If you compare the whole experience... It's a different story!

Here are some of my main complaints regarding my first Sky Express experience:
We visited the Skyserv lounge, where we were told, that they will call our flight to board, when the time comes. They did make announcements for some of the other flights, however not for ours. The airport's website still showed our flight to be departing on-time, however other sources were indicating a 30-min delay as a minimum, so it was a bit unclear (and the gate was even announced quite late, after we went to the lounge, which was at around 70min prior to the scheduled departure, and it was, of course, a bus gate, so not so easy to just jump out of the lounge and check, oh, the airline didn't send any notifications to my phone about the gate, or when boarding had started, either).

Anyway at around 25min prior to the scheduled departure I asked the lounge dragon if they had any information regarding a delay, because "we should have already been called to board" and after she had a look at her screen she frantically replied "we never got a call from the gate, they're boarding, go to the gate!" After my intervention she also made the announcement for any other passengers still in the lounge, but I have a feeling, that there weren't any others, because after we hurried to a "final call" gate and boarded the bus, nobody else came, even though the bus stayed at the gate with its doors open for an additional 10 minutes! I mentioned the non-call (lol) to the lounge issue to the gate agent, but he replied "we did call, but....!" (whatever that implies)
That bus was by the way the only bus used to board the 72-600, all passengers of such an aircraft can be cramped to fit into just one (so whoever boarded first, must have been waiting for quite a while for that thing to get moving).

Upon reaching the plane I noticed how some passengers seemed extremely eager to board as quickly as possible, even after some ground crew asked them to wait a bit (obviously because the door opposite to the one used for boarding was also open!). I used the extra time there and snapped a few pics of the plane and the sunset (which by that time had become clear, we wouldn't be seeing from the air, the flight actually departed with a 40 minute delay).

Contributing factors were of course the congested airspace and taxiways at that time, but I would argue also the boarding chaos we had to endure. Following "Aegean's" logic, we boarded among the last, since we had seats in row 15 and there are only 18 rows or so in that aircraft (you only go in and out of this aircraft from the door at the back). As soon as I boarded I could see, that someone was sitting in my seat! I immediately let the FA know, but instead of doing what I expected (asking that passenger to relocate), she went to speak to the only other FA (and possibly cabin chief), only to come back 5min later and start asking the lady in my seat about more information regarding her seat reservation, which led to her asking 4 other passengers for the same thing, which led to a few of the refusing to vacate the seats that didn't belong to them, which completely overwhelmed both FAs, which led to more delays until things were somewhat sorted out.
People who refused to move claimed their boarding passes didn't even have a seat number (how does someone check in, doesn't select any seat and then the airline also doesn't automatically assign them ANY seat just to maintain some order is completely beyond me)! Those same guys were playing video games on their phones or watching videos on Instagram until several minutes after takeoff without headphones and the volume turned up as high as it gets (and while at 14.000ft cellular coverage wasn't good enough for online videos, the offline games continued until we landed). I don't want anyone to get the expression, that I hate people or anything, to be honest, that didn't actually bother me, but it's shows two things: How some people go about using common sense or good manners and respecting others and how different the type of passengers are on Aegean and Sky Express flights (I've also seen Aegean's passengers do some weird things, but never that intrusive).

The overhead bins in the atr are small! I mean really small! Between the two of us we had a really small carry-on (not each, in total, just one for both of us) and the space in the bin above our row was taken up by a much bigger carry-on and a....pouch! You can't even call that a purse, it was really small, but still took up just enough space, that our bag wouldn't fit! I pointed that out to the FA, but, again, she didn't do anything! What happened to putting smaller items under the seat? Not yet implemented at Sky Express. Aegean's FA's would have immediately asked the owner to put that item under a seat, we even thought about putting our carry-on there, but it wouldn't exactly fit. So the FA took it 8-9 rows further up towards the front, which completely beat the purpose of my booking the 4th to last row, in order to be among the first to leave the airplane at CFU, where I was pretty sure we'd park right outside the terminal and just walk inside, which is exactly what happened. Only now we had to wait for almost everyone to exit the aircraft until we could retrieve our only piece of luggage.
Since each bin above each side of each row has enough space for 2 carry-ons I am fairly convinced that there were people who were seating further up towards the front, who boarded earlier, who actually put their carry-ons in whatever space was free at the back as they were boarding.

By the way where do the checked bags end up on the atr? The reason that other door was still open when our bus reached the aircraft, was because they were loading some bags from that side! Do they go in the tail? That'd be something, there's no way there's enough space there (plus balance issues?). Could it be that they sorted out some small checked bags and put them in the bins instead? I don't know... Anyway, for a flight that wasn't even full, this was very poor handling and a total mess made out of the boarding process! Next time I see anyone complaining about boarding at the Aegean sub-forum, I'll link to this post.

The air conditioning was shut off during takeoff and the first 10-15min of the climb, probably to allow for more thrust from the engines. Which of course caused me to sweat all the way down to my underwear . Even after it came back on and despite the air coming out of it being fairly cool and the cabin much smaller than the one in the A320, it didn't really get the temperature down by much.

Anyway, the rest (what rest? anyway..) was smooth, since we had no checked bag (only here for 35 hours), we were even served a small cookie and drinks (the choices there being water, Amita juice and coffee).

I'm flying back again on GQ in 21 hours, I hope they do a bit better, because that was a let-down. I guess since at ATH we'll be all bussed to the gate it won't matter where we're seating or where our little carry-on will be, so that's one issue taken off the list.

One positive thing about the whole experience was the Skyserv lounge (other than the issue I already mentioned). The Goldair lounge was packed, so I took a leap of faith and despite all the harsh critics I've read here repeatedly I used two Loungekey vouchers I'd come across at some point last year (which worked out great) and finally checked out that lounge (Skyserv) myself. Surely it lacked warm meals, but everything else was more than enough for me, plus it had the best warm chocolate I've had in a couple of years (in a lounge I would argue even ever!).
Again, people being part of the issue there, as groups of 3 would put their stuff in 4 other chairs and take up an entire section of seats! Others would randomly enter, seat at the designated area for people with reduced mobility and basically flip off the dragon when asked to show boarding passes... Youngsters (not that I'm that old myself)... Gives you an idea about what's going on in the world today.