They need to change their slogan to:
"Allegiant Air: We'll get you there... eventually"
I've flown Allegiant multiple times (they're the only direct flight from Vegas to Monterey without selling your first born child) and it's never been without incident.
They are super cheap but that's the trade-off you get in return for efficiency.
My advice, should you choose to go with them, always allot 3-6 hours of open time because you'll never get anywhere on time even if it's only an hour flight like mine were supposed to be.