I stayed at Marriott Goa in Jun 2013 and was very happy with the hotel. The location is excellent, in the heart of Panjim, very close to Panjim market and also river cruise boarding spot. The ambiance of the hotel is quite good and welcoming. The staff is pleasant, helpful and unobtrusive. The buffet spread is quite good and tasty.
The pool is quite big and borders on to the sea, giving am impression of a continuous water body. The hotel does not have a private beach but a part of Miramar beach can be approached only from the hotel, making it a de facto private beach. The fitness centre is also quite good.
I did think of staying at Taj which is closer to Calangute but decided against it. I am happy I chose Marriott which provided quite the same ambiance at a lower price and was better located for my requirements.