Over 40 trips to Cozumel so I can give you my opinion. Aldora Divers, no one else will come close. They will handle your gear for you so once you hand it over you won't need to shlep it around. They are about 15-20 bucks more per boat dive but you'll get almost twice the bottom time so it's well worth it. Fast boats small groups and they are usually on the reef before everyone else. Palancar is a name for the largest section of the same reef that stretches from the south end of the island and wraps around and heads northeast up the island. Current runs basically north(northeast). Palancar-gardens, caves, deep etc, are just names that have been "labeled" to different sections of the reef. Maracaibo and Barracuda are more advanced reefs at the south and north end. Probably the best reef's to do are Paradise and Chankanab. They are great "second dives" relativley shallow and with a good guide or good eyes you'll see more "critters" than you're going to see in 5 dives on the deeper walls. If your staying in a house there is good grocery store across the street from the Plazas Las glorias hotel on the main road that runs along the water. go north to the traffic light( by the soccer field) and there is a street to the right, go right and about a block up on the left is a very good "panaderia" bakery. Downtown San Miguel has gotten kind of crazy with the influx of the cruise ship crowd but if you go there on a Sunday go to the square in the evening and watch the festivities. A few blocks behind the square is a great little minature golf course, If you have time rent a jeep or car and drive the "loop south" around to the back side of the island and hit some of the little shops and beach bars, head north and when the road turns to the left stop at the bar there, try the ring toss, leave a "T" shirt on the ceiling and follow the road straight into town. Try to allow at least a couple three hours. If you need more info PM me I have numerous friends that live there. Dive Safe-Dive Alot-M