Riviera Maya options
We stayed twenty miles south of Playa del Carmen in November. We fished with Pesca Maya 1 day, fished on Cozumel 1 day, and fished in Cancun 1 day. All were great and very different experiences.
Pesca Maya picks you up at your hotel, which is nice, however, they are also the most expensive of the three. The drive can be absolutely hellacious, but is worth it in my opinion...just don't drink too much the night before. April should be the best conditions for Permit, and this is the place to get one. Bonefish, Tarpon, Permit, Snook, and Barracuda. Excellent guides.
On Cozumel we fished with Aquarius flats fishing (aquariusflatsfishing.com). The owner Carlos will pick you up at the Ferry dock and drive you to the marina. The flats are much smaller than where you fish with Pesca Maya, but the fishing is quite good. Caught bigger bones here than Pesca Maya, and saw a lot more big bones on average. No Permit, no Tarpon, but great bonefishing. Guide was very nice but spoke very little English.
In Cancun we fished with cancuntarponfishing.com for baby tarpon. This was an absolute blast and I would highly recommend for anyone traveling to the area. We literally fished within view of the airport at one point. The owner Martin was very good about arranging all the details, and our guide Mauricio was a lot of fun, very competent, and a good English speaker. We hooked a bunch of baby Tarpon, and even caught a few. November was not the time of year to be there for other flats species, but my understanding is that bonefishing and permit fishing should be good in the Spring.
Hope this helps.