i've narrowed it down to either the white manta or la mahe. i'm a mid 50s diver so an older crowd would appeal to me. i also love good food. any feedback from people who have been on either boat?
Different amenities, but I would say: your choice mainly depends on other people on the boat on the same trip. If there are lots of couples/a big group on one boat, I would recommend the other one.
In general I would say, chances are on the White Manta will be less couples but a greater chance of a big group. So simply check with them or your agent.
Both are getting fixed up for this season. I've heard from a DM on the White Manta that she's much nicer now than before--ensuite bathrooms in most cabins, for example.

White Manta is very nice, all newly done for the season - just waiting on some "official" photos. Le Mahe is in Thap Lamu, not yet ready - I was going to head up there today but the weather the last couple of days has been bad so we will probably go first week of October. I would lean towards White Manta. Though to be honest I don't think either of those boats will have an "older crowd"... not young backpackers to be sure, but they are mid price and will get a mix of guests.
The White Manta has a great cross section of clients, and her chef last year was incredible. Heaps and heaps of great food.