FlyerTalk Evangelist
Join Date: Nov 2000
Location: Atlanta, GA, USA
Programs: Frontier Gold, DL estranged 1MMer, Spirit VIP, CO/NW/UA/AA once gold/plat/comped gold now dust.
Posts: 38,151
Frontier has a better vibe to it than Spirit as well. Maybe it's from having some FAs who pre-date the full-ULCC period. I think the cabins are slightly better, and of course with Frontier you can get an ice water to drink free.
As mentioned, some disadvantages with ULCCs are pretty common for all of them.
It's not for everyone, though. For many families and other infrequent travelers who pack a lot, Southwest could still be the best bet.