Porridge, I hope I'm not bursting your bubble too much, but I stayed at the Sheraton Fota Island and it was quite disappointing.
You're right, the spa looks fantastic. However, use of the hydrotherapy suite (for 40 minutes if I remember correctly) will cost you €25. It is enjoyable but I wouldn't have paid extra for it, however it was included in the deal we had. The same charge applies for the thermal suite "with tepidariam and hammam". The temperature of the swimming pool was a bit on the cold side and there was no jacuzzi, sauna or steam room which I have found to be freely available in some 3 star hotels I've been in. So if you want to have a sauna before or after your swim it's going to cost you €25 extra for the privilege.
In the bar the service was the worst I've seen in pretty much any hotel I've been in. We sat for 40 minutes with empty glasses in front of us, and none of the staff - varying between 5 and 7 of them at times - interrupted their chatting to see if any of the approximately 20 people in the bar would like a refill.
Drinks & food were not cheap, so it's particularly annoying to have poor service on top of that. It's 2 years now since I stayed, so maybe things have improved, but I still don't feel remotely tempted to try this place again. On a positive note, it is a very good looking hotel, the room we had was lovely, and the breakfast buffet was excellent.