Puerto Rico to Jamaica is part of Carnival Jamaica: TPOL Goes to Candyland & Rum Rum Caribbean Castaway Trip Report.
When I think of Spirit, I think of my childhood friend who flew Spirit from Detroit to Vegas decades ago. He recounted the story of how the plane ran out of fuel, forcing an unanticipated stop. Based on that experience and based on my general disdain for discount carriers (see What’s the Worst Discount Carrier?), I have avoided Spirit. My rank among the discount carriers has changed since 2020 with Easyjet going from worst to first (see easyJet: The World’s Best Low-Cost Carrier). While I have limited data regarding Spirit, I can say that I enjoyed it enough to join the Spirit Saver$ Club.
Routing
I was leaving from San Juan to Kingston, Jamaica. Since Puerto Rico is a model of inefficiency, I was forced to connect through Fort Lauderdale en route to Jamaica (see Oh No, Not Spirit! Wait, Why Am I Connecting through Panama?). I could have taken Spirit the whole way, but then I would have to spend one night in FLL. Instead, I booked a flight on JetBlue to FLL, crossed my fingers that it would be on time, and was happy when it was.
Plane
Spirit doesn’t help itself by painting its planes this hideous yellow. 
Upgrade
With my Amex travel benefit, I booked an emergency exit row and paid for a carry-on bag. The price to upgrade the seat was a reasonable $26. The price of the Just for You bundle, which includes the following, was an excessive $82.
– 1 Carry-On Bag
– Shortcut Boarding
– Pick Your Seat (Standard Seat)
Journey
The seat was comfortable. The flight was short. We left on time and arrived on time.
Overall
In hindsight, it would have been better to pay for the status match than the Saver$ Club. With a canceled Amex Business Platinum (see Keep Vs. Cancel: Amex Business Platinum), I won’t have credits for a carry-on. I would fly Spirit again under two scenarios: if I can find a rock-bottom Saver Club fare or if I’m flying with no bags.
How about you?
I flew them once FLL-ATL. $32 fare. Was great for a 90 minute flight other than being 3 hours late.