The one Airbus 319 flight I've taken had seats that reclined and more than the usual leg room, at least in the first few rows. Nice plane but not as new as the usual A320s.

At least initially, I'd ignore the whole $9 fair club thing; instead, just buy your tickets at the airport counter and save the $17.99 "passenger utility fee" each way, i.e., $36 per round trip. It's well worth it if you're buying multiple tickets. That what frequent Spirit fliers do. (To be clear, this means you'll pay $36 less than what the web site shows.)

The other key is to travel only with a small carry-on, which is 100% free. Technically, it's supposed to be 12 x 14 x 16, but in practice a medium-sized gym bag that you can stuff under the seat works fine.

Despite what you may have heard, there are in reality only two downsides to Spirit. First, no Pre Check or elite lines. (For me that's a significant issue.) And second, if your plane has a mechanical problem, you may be out of luck if you really need to fly that day since Spirit doesn't have (i) spare planes, (ii) other empty flights to put you on or (iii) reciprocal agreements with other airlines.

That second point is the key. So far I've been lucky.