Reid's been renovated, so you'll get a lot of third years saying stuff like 'Urgh Reid was gross when I stayed there' but FEAR NOT, I hear it's really nice now. I've been living in Wedderburn since September, and recently I've had an epiphany re: accommodation and would say that if I were to choose again, I'd go for either Founder's or Kingswood (if I had a car. You need a car if you want to not be pissed off at how far away it is) because they're way more fun than Wedders. Thankfully, my best friend lives in the block next door so I'm not totally isolated from my social life.
Also, if you've got an unconditional offer and you've accepted it, then you're pretty much going to get your first choice of accommodation (or rather, it's highly unlikely that you wouldn't, because then why would they bother with the preference system). That's also the case if you're an international, it's just the way they do it if they know you're coming for sure. The chances of this get lower and lower depending on how far away you live, whether you've a conditional offer etc.
When I first applied to RHUL, I thought I would hate living in a big hall without my own bathroom and with 30 other people on my corridor, but it's actually a bit miserable living in one of the newer blocks, I've found. You live with only 7 other people, and it's a bit intense sometimes. But, my kitchen's always nice and tidy and of course having my own bathroom is pretty great.