KEF 600c vs R600c (or B&W CM 2 S2?)

[backtothefuture]

I'm looking to upgrade from my Q200Cs which I feel lack a bit of presence and clarity at lower volumes. I have a Yamaha 3050 amp driving these. My fronts are the Q300 bookshelves.

Online reviews on Amazon are very positive for the Q600Cs ...haven't found many reviews for the R600C ... a hifi dealer said that the R600 may stand out too much (compared to the Q600) as being of superior quality..hence I may get a mis-match with the Q300s... not too sure about this

Another hi-fi dealer recommended the B&W CM 2 S2 which he has on offer and compared it to the R series.

Whatever I spend now on a center speaker, I intend to hold it for a good few years so just want to make sure I get the appropriate one. Any suggestions? Cheers!