I flew Allegiant Air in Sept 08 from Des Moines to Las Vegas. I appreciate the direct flight and not having to do the connect routine. The employees as a whole were friendly, and even had one cracking on a co-worker--all in fun. The flight I was on was almost all Iowa State Cyclone fans flying to Las Vegas to see the team play UNLV.
To get in the spirit of Vegas, the flight attendants offered all passengers the chance to throw 5 bucks in a bag (with the seat number on the bill), and then gave the bag of money to whoever's bill/seat assignment they pulled out. I think 120 people played on my flight (I didn't win-boo hoo)
One guy also got the flight attendant to play the Cyclone fight song over the intercom. Nice to see a company empowering their employees to make a decision to have a little more fun for their customers--instead of saying "that is against company regulation 34.C.7, blah blah)
When purchasing, see the price and raise it by 25%. You will get nickel and dimed. I don't have a problem with that, just be aware of it. $2 for an inflight can of pop (or soda, depending on your geography)--which isn't horrible, at least compared to going to a ball game. If you don't like it, just carry your own on. Same with food.
I think Allegiant is all MD-80s, which is a decent plane with 2-aisle-3 seating. Seats were leather, and comfortable. I flew in good weather, and all went well. We all have airline horror stories, and I'm sure Allegiant has their share. But this was an opportunity for all to go well, and it did--on time, and all bags and people arrived in one piece.
I think Allegiant Air's story is a great idea--fly non stop from smaller markets to serve the vacation traveler--increasing the opportunity and ease for those of us in podunk to easily get to vacation hotspots.