We were on the Grandeur of the Seas from Oct.5th til the 14th and one of our ports was Samana....... not much to see or do there at all!
I had asked this same question before we went on our cruise, and I stayed on the ship because I had concerns about the long tender ride. It took longer than the tender to Labadee and the tenders were not the same ones at all.
If you want you can send me a PM with your email and I can email you some pics from Samana, you can see for yourself what it looks like. My son felt so sad for the dogs that were roaming around, he wanted to feed them! They had a place where you can buy things, like paintings and tshirts and assorted other things. One of the pics my hubby took show a soldier standing there with a rifle strapped on his back, maybe this is common in this part of the Caribbean.
It was a very beautiful island with lots of coconut trees, and the tender operator took them along the coast on the way to the dock in Samana and they took lots of very pretty pictures.
So if you want I can email you some of the pics my hubby took, just PM me and I'll send them off and you can decide for yourself about Samana. I don't have any info regarding the snorkling there, but I do know that a lot of ppl went to the other island called Cayo Lendtado(sp?) and enjoyed it a lot!