I flew them last christmas/new years season from NY to Phoenix.
There is a reason they are cheap.
This trip involved 4 flights -- 3 going there and direct back. ALL 4 flights were late to varying degrees and not because they waited for each other. I noticed that some of the terminals they use have ads for both Continental & America's West (aka America's Worst, the airline that actually rates their own flights as having a 10% chance of being on-time), they might be merging or something.
2 of the flights used the "ExpressJet"s, which are tiny planes that have only 3 seats per row (1 on left, 2 on right). On both of these flights, there was a delay because they had to have people change seats to the back and/or add sandbags to the luggage compartment to "balance" the weight of the plane.
The second flight spent about 90 minutes circling Houston airport (continental's main hub) in the air because they had an air-traffic jam there so apparently every flight into there was delayed). It finally landed less than 3 minutes before my connecting flight was supposed to leave so I sprinted across the airport to catch it. This had to be over a mile easily. Fortunately this flight had also been delayed about 25 minutes and they had people moving from one terminal to another because they changed which one it would leave from at about this time. My luggage did not make this connection and arrived at its destination 2 days later. I wasn't the only one in line at the baggage office who made this particular connection either, but it was a bit too complicated for them to figure out I guess.
Continental couldn't track down the luggage for most of a day, even though it still had the nametags & flight path stickers on it when I got it. They were claiming it went through cleveland somehow. (Flight path was newark->dayton->houston->phoenix).
One of these flights had an in-flight movie, and I found out the wonderful new policy on this..... the crappy headsets if you want audio with your movie are no longer free. You get to pay $5 for headphones that go in the special airplane audio jacks.