I've just started using Rook recently. So far so good. I've almost exclusively used another (very good) platform for the past 18 months but moved a bit of stuff around the last couple of weeks. Rook have given the best results on those that I've tinkered with. Of course YMMV.
Another note - my account manager, Mike Morrison, has been genuinely spot on. Looked into things properly for me as opposed being fobbed off with generic comments or one liners, as is sometimes the case with others.
So guess what, I will keep using them.