As a mature student, I turned down a Russell Group university in favour of a 'poly'.
The city I'm studying in has two universities, a red brick, and a smaller CG (Cathedrals Group) university. The Russell Group uni was several miles out of town, so was isolated, sprawling and absolutely impersonal. My first thought was that it was like a Tesco. I don't particularly like the ideas of lectures with or seminars with hundreds of people, and presumably a struggle to book a meeting with a lecturer or tutor.
The inner-city uni which I chose over it, is by comparison much smaller, with lovely Victorian buildings, small classes, and the department staff, despite being extremely academic, published authors and respected academics, are extremely approachable and helpful. My only criticism is that a smaller uni has a more limited scope for modules.
I don't think Russell Group uni's are particularly important to a degree, and, as an earlier post says, are largely a lobbying group. I also don't think that so many employers are bothered nowadays, as unless you go on to do a Masters or PHD, a degree on it's own is largely worthless, in matter where it comes from.