I have not been to Ponderosa. So I cannot say anything about this dive.
I have been to Tajma Ha. I have no issue with enclosed spaces. That said, there is a few points which I think are a little tighter in Tajma Ha then the other cenotes. In particular there is a steep descent when you have to drop rapidly for around 30 feet. I think that area might feel a little tight for some people. For me, I have issues clearing my ears and I actually had to wave for the guide to slow down in this area because it was suggest a steep descent.
That said, I went to Tajma Ha REALLY early in the morning (got there before 8am). We were the first people there. The water was totally undisturbed. REALLY beautiful at that time of the morning.
Chikin Ha was an okay dive. Fairly open, easy and interesting. On that dive we also came up at Taak'Bil Ha just to have a look around. That was kind of cool. Maybe google for "taak bil ha" and you can see some pictures of it from above ground.
Dos Ojos was actually a great dive for seeing fossils and things. I think in part this was due to our guide, Thomas Bolbrugge from DiveMex. He gave us a briefing on what we might find there and during the dive pointed out things as well. You will most likely have the guide take you over to a map of the cenote. During that time you can mention you are interested in fossils and things. Hopefully they'll take note of that and point things out for you as well.
If you haven't been to any of these before, I think you'll be in for a treat no matter which one you go to. All of the ones I was on were real cavern diving and not just swimming in a basin. The recommendation to ask the guide from CenoteXperience is a good suggestion as well.
Darrell