Nice hotel, but a bit inconvenient. If you can stay in the hotel and not going out much, that would be better.
They have a lot of varieties for their breakfast. And they have a resort feel like hotel and swimming pool.
Actually there is a small mall opposite to the hotel that you can make your "boots" shopping. There's also MacDonald and KFC there. If you really insist to go out, you could take the hotel ferry that runs at 15mins interval to Saphan Taksin, and from there you can get to Siam easily, around 15 mins BTS travelling.
It is a nice hotel, good for relax!!
If you don't want to get the shuttle ferry to BTS for shopping, you can simply get a taxi for shopping mall that is near the hotel. e.g. Big C (~7mins by taxi), Central shopping mall in Rama III (~10 mins by taxi), Lotus (~10 mins by taxi).....
The breakfast is wonderful!!!!
If you have 3 days and 2 nights only and want to do the spa, I think you better consider the Mandarin at Macau. The spa there is also good. Until end of June 04 from Mon to Fri, you can have one night of free accomodation if you buy two spa/message treatments with AE card.