We visited Chankanaab last week. There will be something there for you both, lots of sunbeds under umbrellas right in front of the snorkelling area. Not too badly priced we didnt think - I think it was something like 23 dollars for plain entry, and 28 dollars for entry + snorkel hire.
We got the ferry across from Playa 170 pesos one way, and the taxi was about 150 pesos down to Chankanaab.
We've been to both. If you are on the mainland, of course Xel Ha will be easier for you to get to. It costs a lot more to get in than Chankannab and I can't recall if there is much area for the one who wants to lie in the shade and read. (?) Maybe someone who has been there recently can help answer that? I do feel like there was a lot more area to snorkel in there though.
Chankannab has place for lying around and reading, but you have to take into account the cost and time of getting there. Ride to ferry, ferry to Coz, a ride from the ferry, etc. If i were going to take the ferry and such over from Playa, it would be to take a reef tour on a boat. The snorkeling is much better, but it sounds like no fun for the person who wants to read in the shade. :)
Anyway, they each have their pros and cons but i'm sure you would enjoy either place. If i were trying to choose between the two, i'd go with Xel Ha just because I don't want to spend half the day traveling back and forth to get to the destination, but thats just me. (When I visited Chankannab, i was staying in Cozumel)
Have a great timeEdited: 1:22 pm, August 17, 2019