To begin with this hotel has a very pleasing contemporary feel. From the lobby with its neon lights to the corridors that resemble a cool dormitory it definitely has a distinct Euro vibe.
The room was spacious, with a small flat screen TV and a comfortable bed. The glass shower in the middle of the room is an exhibitionist dream. I wouldn't room with a friend or mother in law though. Could be a bit awkward.
Air conditioning, on the occasion I stayed felt non-existent. They provide a fan to help cool things down, but, it was not always comfortable in the room when the temps were in mid-90's outside.
The location was good, very close to the offices within the city and one stop away on the train from the main train station.
The breakfast was very good. Lots of hot and cold options.
The service was very good, with friendly people at the front desk. They even helped me negotiate my cab fare back to the airport and lent me a few Euro cents so that I would not have to go to an ATM.
The gym was great. They had a whole Spa area with dumbells, treadmill, eliptical and had a sauna and showers for guests. Very nice and upscale.
Overall I had a good stay. If they would have better air conditioning, it would have been perfect.

This hotel certainly has the wow factor, especially the glass elevator right in front of the lobby.
Check in was smooth, and by signing up to the Melia card, breakfast is half the price, which was a great deal. Signing up only took a matter of minutes. Staff couldn't have been more helpful.
As others have noted, the shower is in the middle of the room and see through, which might bother some. Since I was on my own, it wasn't a problem. What was slightly annoying, and also noted before me, was the fact that there was nowhere really to put your shower gel and shampoo in the shower. I'm not sure how that could happen.
Room was very quiet - the insulation was great.
The hotel is located in a business part of Frankfurt, but on the outskirts, not far from the airport. I knew that going in, so it was perfectly fine. The train station is about a 10-15 minute walk away.
I'd gladly stay here again. The price/quality ratio is excellent.

There are few reasonably-priced options close to the airport, but this hotel is a convenient next option. It is only a short and cheap train ride away. The hotel is very sleek and modern. The rooms are large and comfortable with floor-to-ceiling windows. Not really a room for sharing with a friend unless you are close and not modest: the showers are glass-encased and in the middle of the room... my husband and I liked it but others may not!

When going there you should be prepared for two things: 1) It is located in a business district, so it is VERY quiet on the weekends with hardly any other places open nearby (though the hotel restaurant was quite good). 2) It is a 10 minute, zig-zagging walk from the train station. We were lucky to have a kind local take pity on us and walk us there. If you arrive on a Saturday or Sunday, you should have your directions prepared since there will not be many people in the area to help. Another tip if you have an early flight is that the wonderful market at the train station in the airport is open as early as 05:00 (I think even earlier), so get a fresh breakfast there.

Excellent view, nice location and very stylish interiors.
I went there for a business trip and experience was mind blowing.
Rooms are based on new concepts, spacious and supported by cooperative staff.

Also i am Asian Veg (cant take eggs, meat or non veg), i was blessed to be at such a place when i am outside my country as they could prepare things for me outside their usual menu as well at odd hours also. Glad i selected this hotel.