2 weeks ago I stayed for a night in the Royal Bayswater Hotel and it sucked. Despite the receipt from HostelWorld.com, I was forced to pay more when I arrived than the receipt indicated. I was jetlagged and had 3 other grumpy people trailing behind me so I paid up and figured I could work it out later. Our room was a dump, the sheets weren't even on the bed. When we went down for breakfast the next morning we kept getting harassed because the people working didn't think we really stayed in a private room there, but thought we were supposed to eat in the basement (getting a private was supposed to mean a larger meal in the morning as opposed to what you got if you stayed in a dorm).
There didn't seem to be much of a common area that I could see. Some internet computers in the front. No real character at all. And it was 5 GBP (about $10) for the towel deposit which is a lot. We got it back, but still was kinda ridiculous.
I wouldn't recommend it to anyone but if you do stay there, hopefully you'll have a better time of it. And also, every other hostel/budget hotel i stayed in was awesome, i'm not just a snob who hates hostels. I promise.
Full Disclosure: I am 26 years old, travelling with my 26 year old wife, 22 year old brother, and 18 year old sister. We always stayed in a 4 person private room. This could definitely skew our impressions so I wanted to include it.