From someone living in westwood:
Pros:
Close to tesco and Canon Park, and you have to carry more from tesco than you need to to your lectures...
Not really that far from campus, if you have most lectures in the maths and stats building, there is a shortcut, I can run there in under 3 mins and walk in 5-7mins, I think it's actually closer than Sherbourne/Lakeside/Heronbank, and possibly than Rootes.
Good value for money, the rooms are bigger than Rootes for almost the same amount.
Quieter at night because it's far from the SU
There are 8 blocks, and 4 have really new bathrooms and kitchens (2 years old now I think) which are great, I only share a kitchen with 8 people, I think it's 12 upstairs but the kitchens are bigger. The other 4 blocks aren't as nice in that respect but have massive common rooms whereas ours is a bit smaller. I share a bathroom with my floor of 18 and there are 4 showers, but I've never had to wait for one and there has always been at least 2 free when I've needed one.
There are also 4 toilets, and again, never been a problem.Ground floor has a common room and a dining room and it's great to have places to chill, sitting in the kitchen while people are cooking is hot, noisy and not ideal really.
There is a field in Westwood and that is becoming rare due to all the building work, it's nice for picnics, games etc.
The Avon building in westwood always has loads of free computers, a printer, sofas and is generally a good place to work, doesn't get full like the learning grids in exam season
39 week lets, moving all your stuff out in holidays would be an absolute pain.
Cons
The distance if you're lazy/a humanities student
You don't have your own bathroom, but you do have a sink in your room
Older blocks have small kitchens for the number of people (unsure about the bathrooms)
washing machine and dryer per block, sometimes this is not free, but it's usually just a case of coming back in half an hour, as the laundry room is in your block you can just leave your stuff there, set and set an alarm for when the person before you is done.
A word about other blocks:
Claycroft is without a doubt the best located, especially for maths, it's next it tesco, but it's post grad next year
Bluebell is really unsociable, EVERY door locks so you can't visit other kitchens, there tends to be a small number per kitchen, my friend who lives there never sees his flatmates
Rootes is ok, but worse than westwood in that the rooms are much smaller, it's also not that near to buildings where lectures actually are (have a look at a map), it's social but not really much more than other blocks, you just have to find the right kitchen.
Sherbourne/Lakeside/Heronbank are actually pretty far from central campus tbh, I'd say the worst location, particularly for maths.