Sounds like you're set on downtown, but if you are considering south and paying a taxi into town for supper, I'd suggest Casa del Mar. It's small. It's resorty. It has a restaurant. It's free pickup from the dock. It's 80 pesos to the malecon by taxi. Nice shore diving out front. Ernesto's Fajita Factory is right across the street and about 3/4th of a block away is the other neat restaurant whose name I can't remember. They service the Tikila bar right across the street. It takes me 45 seconds to get from the furthest room to the restaurant. You absolutely want a balcony room there if you're diving. The cheap rooms are too small for 2 divers. No time share people. It's quiet. We wait for everyone to get to the lobby before we ask for a taxi because the taxi shows up so quickly. Also, they have dive lockers right on the dock. Super convenient. Beautiful grounds. Lovely people.
As to nitrox, last trip was 2 weeks. We slowed down near the end but still did 42 dives. No way I could do that without nitrox. Years ago I'd dive like that on air and when I switched to nitrox on 2nd and 4ths, it was a world of difference. Anecdotal or not.
Personally, I'd rather take a taxi to supper than the caletta. When I'm tired, and after 4 tanks a day, even with nitrox, you feel it, it's easier to be dropped off right at the restaurants door than to walk 3-5-7 blocks to supper. On the other hand, if you're doing 2 tanks a day, a little nap before supper should make that a non issue.
For now, if Allison is your comfort zone, stick with her. You're there to dive. But, there are many really good dive shops that will pick you up at Aldora's pier. (I think there's another pier down there too?)
-Blair
