I've flown to different destinations on Spirit a number of times in the past. After each flight I tell myself "never again", but then, probably because of their seemingly inexpensive pricing, I get sucked back into booking another flight with them. It's only inexpensive if you want to be guaranteed a middle seat usually near the back of the plane. All other desirable seats (aisle for instance) are bought up ahead of time by those who are OK with spending extra money on a chosen seat. That's fair, I guess. Southwest, in contrast, gives you a much better chance of getting a good seat without the necessity of "buying" the seat you want. Not to mention the liberal carry-on baggage policy on Southwest.
Anyway, the combination of horrible seating, expensive baggage fees, a difficult to navigate website (try getting an electronic boarding pass), delays, and poor customer communications this was the last time my temptation to fly with Spirit will get the best of me.