My first choice would probably be Benefactor, but all the people I've spoken to say they don't know much about it and there aren't many comments about it here so I was wondering if anyone could give their opinion on it.
Bluebell has a few things going for it: Wifi in the kitchen, ensuite, bigger beds, modern styling.
However, the cost is extraordinary! It's not worth it. It's individual flats, so if you don't get on with your kitchen, you're not in a good situation, and you simply have no money left to enjoy yourself for the rest of the year!
You need to do your own research and come up with a criteria. The best hall for meeting people will be Rootes, but it's noisy, out-dated and shared facilities (if you care about that). Decent sized rooms are available at Westwood, but it's about 10-20 minutes off central campus. If you want ensuite, go for Jack Martin, Arthur Vick or Lakeside. Lakeside is also 5-10 minutes away from central campus, but it's 39 week lets unlike the other two. Jack Martin is closer to the SU than Arthur Vick, but AV has a common room. However, they're only 30 week lets.
There's a lot to think about. Just write down what you're looking for in an accommodation block and match it up to what's available
You definitely get what you pay for with Bluebell: it's on central campus, 39 week let, lifts, WIFI in kitchen, double beds, ensuite and it all looks very modern. Far be it from me to tell you how to spend your money but I think it's just not worth paying £6000 for when there are perfectly good halls available for much less.