Hi
I've been doing some research and remember a thread about this some weeks ago. The general opinion appears to be that Bristol is the absolute tops. OATS have great notes and I believe good success rates but their marketing department told me that the £2000 'special offer' will probably end this summer. So if you want it, be quick about it. I personally though don't want to pay OATS any money at all because they're soooo unhelpful.
Hope this helps
Nige