[excession]

Betfred and NOIQ are two of the better ones.
Obviously across the same network you are talking about bonuses/RB and afiliate rake race comparisons.
BetFred is very very solid financially (they have hundreds of B&M betting shops here in the UK) so if you are a higher stake player then that would be a safe choice.

I'm with NOIQ and perfectly happy with them, though don't know much about their financial base so keep my roll there under $3k usually..