Basically when it comes to receivers you want to find the one that has the features you want and or need. For home theater you want to find the receiver that has the best processing ability and you can look at various home theater magazines.

When it comes to the actual sound of the receiver there are relatively serious compromises some of which are more or less evident depending on the speakers, the kinds of music you listen to, budget, experience of the listener, and general expectations you personally have.

I have not heard the new 600 series but the old 600 series was fairly accepting of anything. Most receivers sound very much alike to such a degree that I would place the biggest emphasis on features and durability and how good the remote control is. Don't discount the ergonomics. Buying a receiver is arguably a sonic compromise so if you are going to make it you may as well tip the scales as far as you can to what receivers offer. The best features, the most ergonomically sensible unit and one that is simple to use. The British units in my view are still compromised and often rely on name brand recognition and a certain "prestige" factor that IMO has left them. Arcam is not as good as they used to be for example and they have converted more to feature boxes but rely on their "name" to suggest a premium of sound over the Japanese units.

You may of course still like a Rotel or Arcam better and they may very well be better - but be sure to really listen to them with the B&W's and go over all of the features the units offer. Do the homework and do the listening. You will feel a LOT better about your decision than relying on others to decide for you.