Hey,
I just recently completed my DM at Buddha View on KT. I spent a little over 2 months there, diving 2-4 times a day. Although BV is one of the larger schools they operate 3 large boats, and occasionally a speedboat as well, so things aren't generally too crowded. The equipment they offer is...so so, but I was diving with my own gear. Mark is great!! Really nice guy and definitely knows his stuff. Also the group of instructors is really good too, good attitudes and good teaching manner. I can't comment a lot on the diving since most of my dives have been in Thailand, but I will say that there are many dive sites very close to the island, lots of fish life, although perhaps not as many exotic species as other places, and the last month or so I was there the deep dive site...Chumpon pinnacle...had a huge influx of 2-3 meter reef sharks in addition to nice schools of batfish, baracuda, trevali, etc. Corals in and around Koh Tao are not the best...on one of my last dives there we found the one lonely soft coral growing umolested out in the sand. The lifestyle on KT is a good one...very chilled out for the most part, although there is allways a party going on someplace on the island every night. Buddha View is located on Chalok Baan Kao beach, which is much prettier and more layed-back than Sairee. Plenty of accomodation to be had on the beach, or nearby, for not a lot of cash. I may go back next year to do my IDC at buddha view. They have a very nice (air conditioned) IDC facility. Thumbs up from me.
Dan