Lovely new hotel with sweeping views of the river. Very friendly staff, there's a shuttle boat service to the BTS station and the River City Mall across the river.
The breakfast is great though not exceptional, and the Flow restaurant/coffee shop is beautifully designed with the lobby spilling on to it and the restaurant spilling on to the river.
The other restaurants seemed ok, but didn't have any 'buzz'. Maybe that's because the hotel is new and will get popular with time. We went to the rooftop bar and the other bar/club on a sat. night and they were quite deserted!
The standard rooms are quite small though. There's no proper work desk/chair. If I'd been there on business, I'd have found working there quite uncomfortable. Even otherwise, there's barely space to leave some bags and stuff. The bathroom is, however, quite generous-sized (they could have put a larger washbasin, though).
Another con is the expensive internet access - 625 baht for 24 hours, which is pretty expensive for a leisure traveller who just wants to check his mail once a day.
The hotel is located on the 'wrong' side of the river, but taking the boat is a pleasant experience, unless you are in a hurry (which we never were).
Overall, I'd think this is the best place to stay on the river at this price range.

I had never traveled in Thailand but thanks to Trip Advisor I was able to plan my stay in Bangkok and Koh Samui easily and successfully. The Millenium was beyond my expectations. The staff was very welcoming. I used the business office to ship souveniers to the US from my earlier travels. They provided boxes and tape and then I also stored luggage with the bellman at no extra charge while we were at the beach for a week. We enjoyed treatments at the spa every day! Especially recommend anti aging facial w/clay and Thai massage a must! Room service food was very good and we also enjoyed the breakfast restaurant...more food than imaginable..and the best fruit . The concierge helped arrange a tour for us but his knowlege might be the one area that could be improved. I would also make sure you have directions to the hotel in Thai or the hotel phone number for the driver to call on his cell as both times we took taxis from the airport the drivers were confused about the location. The taxis were easy to use ,although you need to know the cost of the ride before you get in...they really are too cheap and I tip even though Thai do not...I think it was 500 Bhat to airport w/ tip. This hotel was verrry luxurious with out the stuffiness you might expect. All the amenities you could hope for. What a deal. Thanks Trip Advisor!

Our first two nights in Thailand we spent here. Gorgeous hotel! Yes rooms are small but I didn't entertain so big deal! Location on the river is kind of fun..no problem. Once we took a taxi to China Town and it was only like 150 baht. We found a neat find..on the side of the hotel is a long walkway that locals use to get to the public water taxi. It is lined with street vendors and market shops. You can get great deals. I kick myself that I didn't buy more. If you are Hilton Honors or buy a room on the Executive Lounge, this hotel has the best Executive Lounge out there. Beautiful views, lots of food and drinks. I din't add pictures because I have all the same ones as the previous reviews.

This hotel is great and in keeping with other 5 stars in Bangkok. Staff and service is excellent, river views from all rooms. Rooms are a good size and so are teh bathrooms. Only bigger rooms I've seen in Bangkok have been the Metropolitan rooms at the Metropolitan hotel. A great stay, will be back!