Well, flew with them yesterday and not too bad.

Flight was 100% full.
Priority boarding first including two wheelchair passengers yet there seemed to be half a dozen people on already in exit rows etc.
"A" boarded next and I was at the front for that. Just picked a seat a few rows from the front on the right so I could see the Las Vegas Strip from the window. The person behind me immediately sat in the same row in the aisle so not sure if I beat him to it or just picked a good seat.
15-20 wait after taxiing due to ATC.
Fun announcements and rushed through safety briefing.
Everyone's drink orders taken and then delivered shortly afterwards.

Quite spacious seats. Felt like there was more legroom than other airlines.
Mad rush after landing to disembark.
Don't think it makes too much difference on a short flight from LAS-LAX as to when you board if you are solo. With free checked luggage, there's no real need to fill every bit of space with carry-ons.
Luggage made it.
Didn't notice and "reserving" of seats although near the end of boarding, just a few randomly placed middles left.

Shame they arrived at T1 in LAX when my connecting flight was in T4.