I went to Yap in 2006. I stayed at O'Keefe's and LOVED it!! Beautiful building, great rooms, amazing views. The staff was excellent. Sitting on the porch in the rocking chair just relaxing after diving was wonderful. O'Keefe's is a much nicer, more personal experience than the Manta Bay resort next door.
I did my diving with Beyond the Reef. They were outstanding! They actually picked me up at the airport, threw my bags in the back of the truck and drove me to the dive shop. I went diving that morning. The manta dives were stunning - so close, I actually thought one was going to hit me. The dive master (can't recall his name) was superb. Great personalized service.
After my several days of diving, I also went fishing with Beyond the Reef. Another super amazing experience.
I can't say enough good things about both O'Keefe's and Beyond the Reef. At least back in 2006, they were both second to none. I'd do it again in a heartbeat!!