I know Stu, but I like Manilanite more... less spanish colonial! 
As for Solana's proximity to Twin Rocks, from my memory, it's at least 800m away, not really snorkeling distance for typical tourists.
Kieran
Having been to quite a few of the resorts, including the aforementioned ones, and the fact you aren't too fussed about accommodation as long as the diving is good, I suggest you choose the resort closest to a good site, so that the non-divers can enjoy without a boat. Twin Rocks is my favorite shore dive site and a good site for snorkelers, especially when the trevally stay shallow It's not the fishiest site but it's a cool site with the rocks somehow attracting things like turtles etc. 2 resorts sit on the site, Balai and Planet Dive. Planet Dive has the nicer rooms and dive center and sits directly on Twin Rocks.
A better site for snorkelers is Cathedral, because it's relatively shallow ( I think the top is like 6m) and very fishy (although they are mostly damsel fish). Dive 7000 is within swimming distance (2-300m). It's a nice resort and quite laid back but no real beach to speak of.