As Hillbilly says. I've been whale watching in Samana three times now and Kim's is by far the best. The website is largely still under construction but there are links for contact details.
If you are planning on going out more than once then I'd definitely say stay in Samana. If you're only going to do one trip, then anywhere as far of PoP/Sosua/Cabarete is 'do-able' as a day trip, all be it, with an early start (5am ish).
This shot was taken from a Kim trip last January. I'll go again next January too!
