Note: NSX feel free to move to Frontier forum though it is my desire not to rage bait anyone...

As a long time WN afficianado I was reluctant to fly Frontier but I decided to give it a whirl as WN does not provide service into MSN and I wanted to avoid the time & expense of a car rental at MKE plus a 2-hour drive each-way to Madison. So here goes:

• First step was to purchase the $40 Gold status match/upgrade for 2025 (later $69 thru 2026) in order to bypass many of the annoying garbage fees. If you are in any way considering flying Frontier I highly recommend you take advantage of this opportunity the next time it appears, as it is money well spend and will pay for itself in just one segment.
• Second step was to purchase a ticket - I chose the 2nd bucket (equivalent of WGA or whatever it is called now) as I did not want 100% non-ref non-change ticket. Probably could have saved a few $$ as i did not end up changing anything and unlike WN you prob won't have same-day change options (more on that later).
• Schedule - unfortunately you will find that Frontier does not offer daily service to every destination, unless you are flying to DEN. In my case there were only 2 daily flights from SFO to DEN of which only 1 would arrive in time for my connection. Even worse Frontier only offers 4 flights per week to MSN, so you are up a creek if the flight cancels. Due to scheduling, this left me with a ridiculous 6-hour layover in DEN, but that was the only option. Thankfully only 1 hour on my return.
• Advance seat selection - With status I was able to select Row 3 (more legroom) and Exit Row for no upcharge. Exit row is better as it has more legroom and more overhead space
• Checkin is similar to most airline apps. You will have an opportunity to upgrade seats for cash. Do not do so, as elites will have the opportunity to claim free upgrades closer to ETD. Practice tip: scroll to bottom of BP if you are looking for the button to add to AppleWallet.
• Upgrades - Rows 1 and 2 offer a blocked middle seat and are thus considered the best seating option on Frontier. However I did not upgrade the outbound flights as I did not want to risk losing overhead space. As it turned out all the exit rows had empty middle seats, so I didn't miss out on anything. On the return the upgrade was not showing at T-24 at checkin, but I was able to switch to a row 2 aisle at T-5. No complaints, you would never be able to do this on UA as a low level elite.
• Checked bags - normally I don't check bags but had to make an exception - the fee to add one bag at checkin was $54. Practice tip: purchase in advance if you can as it will save $$ to bundle. The line to check bags was short, the counter agent was friendly, no attempt to hassle me over my carry-ons, and I was off quickly. Practice tip: be sure to use airtags, Frontier app does not let you track your bags or provide text updates on location.
• Gate area - Frontier lucked out with the International gates at SFO, it's a beautiful terminal with great concessions and many PP lounge options
• Boarding - Was told that half the plane is Group 1 (similar to UA at SFO) but that was not the case. Unlike WN, there were very few pre-boards. There was no line for group 1 (again like UA) so I was on board fast. Was pleased to see that the FAs save overhead space for row 1-2 (above rows 3-4) so those who have the best seats will have space. As I was in row 3 this pushed my bag back to the next bin, but still reachable.
• Clientele - appeared to be many infrequent flyers, even more so from DEN than DFO. Too many uncaged dogs, none of which were service animals. looked like any WN flight but minus the road warrior business people. One lady was upset because she paid extra for a carry-on but was forced to check as she boarded late. You snooze, you lose.
• Airplane - Practice tip: Frontier has NO wifi, no IFE and NO outlets. Seats do not recline (I consider that a plus). The lack of chargers can be a problem if you have long flights, short connections etc. So plan ahead, bring portable chargers, charge in terminal, etc. Seats do not recline. I did not purchase any snacks or beverages, but I was happy to see Ramen on the menu. Prices are not cheap, I think $4 for a soft drink.
• Denver hub - "mediocre" and "pathetic" are not strong enough adjectives. This part of Terminal A in DEN rivals the worst gate areas I've seen in the USA. Bathrooms had standing water (ewww) by the urinals. Very few concessions or food options. I have never been more thankful that I on this trip to have Amex Lounge access.
• Flight Ops - we had a 2hr delay to take a toilet out of service. Of course this can happen on any airline, but this seemed excess just to lock the toilet and complete the paperwork.
• Baggage claim - checked bag was already on the belt by the time I arrived. A++

Overall I would have to rate my experience as satisfactory, definitely no worse than my average WN flight, except for the lack of texting and chargers. Seating was definitely better. I would definitely fly Frontier again if the price and convenience factor was right. However I would never use Frontier for a family vacation or a trip where I need to be somewhere soon after landing given the lack of backup options if things go FUBAR