I can't say which is better, as I haven't looked into Brunel, but I can tell you why I'm going to Hull this september.
It's great for employability.
Friendly atmosphere (both in the uni and in the city).
They're always carrying out research.
It seems like a good location.
Accommodation is cheap.
They get good results.
It's a reputable university, without being stuck up.
Hope I helped. Sorry I can't compare the two.