I didn't really have any issues with uber in December. In fact it was super cheap on our airport runs (SJU to Old San Juan was $13 and Condado to SJU was $11!!) Our occasional Ubers around the region were fine too except for a couple rides that I think were affected by the cruise ships in port. On those two occasions prices were about 2-3 times what I would have expected and also took a few minutes to match.

Note: none of this experience has to do with ubering to/from the Hyatt Grand Reserve. Just general uber comments from a visit staying in OSJ.