I don't think you will have too much probs commuting to SJU, last I checked there were about 5 flights/day on AA & NK combined from FLL.
On reserve it's a min of 12 days off in a 30 day bid period and 13 days in a 31 day period. Contractually we are supposed to get a min of 5 days off in a row, but they've only been doing min 4 in a row. On reserve you have 3 hours from being called to departure time, but generally crew sked tries to give as much notice as possible i.e. anywhere from the min up to 36hrs in advance.
I've heard that they hired about 11 guys from SJU that want to be based there- that plus the approx 4 that already bid for it means that 15/23 slots should be spoken for. The other junior bases are ACY/LGA and they have 8 each an it seemed like 4 guys each bid for them.
That hiring projection through Jun has been out there for a while- always subject to change. Could continue longer, unlikey shorter.
I think the overall QOL is good. As with everything in life, it could be better but could be much worse. If you are coming from a regional it will be a huge bump in QOL.