One of my favorite hotels in Bangkok, if not, in all of Thailand.
Let's consider the price first. Chances are, on most nights, you can get a high floor room here. Considering the location (Siam shopping/nightlife), and... that this is an authentic 5 star, you just won't go wrong. The only minor setback: just one restaurant in this entire (massive) hotel. But the fact the restaurant has amazing staff (I've stayed here many times- they always remember me, even by my nickname)... and the food is truly classy, I'm ok with it.
The hotel itself, is elegant, classy... room decor is a perfect mix of modern/chic style, with a hint of bohemian/classic. Very nicely designed rooms, that make it a true 5 star. I'm a fitness buff... so I can't stand hotels that delegate a small room in a basement somewhere, put two treadmills, and a workout ball in the middle, and then say "fitness center" included... this hotel, has a real gym- with real machines- even a smith machine (bench press, shoulder press, etc) with sufficient 20 kg plates around for a serious workout. Full credits to the hotel for this point. It's a big enough gym and very modern too, to feel like you're in a real gym and be motivated. The spa (included, in the rooms) is nice too- with a great steam room, hot tub, and, sauna. Love staying here... a great workout... then relax in the steam room, and then get some amazing food at their restauarant. Seriously, for this price- you'll have a hard time finding better in this area. I know, for I've tried many others in the area, and always end up coming back here.