
Hi Lorripop,
I work in London and have used these quite a bit, but I have the luxury of knowing a lot of the areas and so am able (looking at the Hotel descriptions) to guess which Hotels they are.
In the main it's very rare that you get what we would think of as the 5 star hotels, they tend to be upper mid range and do very much vary! If you do get a particularly nice hotel then it tends to be because the room is one that is situated over a noisy bar area or building works are nearby etc <- now that's not always the case, but if you're planning a nice evening out and want a nice environment then its a consideration!
The last one I booked in the Summer was a gorgeous modern hotel with sumptuous rooms but at midnight the noise was deafening as they had a DJ and pumping techno sound set and we hadn't realised (During the day and early evening it was a fairly quiet very nice Champagne bar) So it pays to do your homework.
If you've spotted some your interested in then feel free to pm me the link(s) and I'll take a look and see if I recognise them and can give you a heads up. If you want to pm me the price bracket you were looking for and area I might be able to give you some recommendations also.
HTH? :-)