The R900's are really good speakers, if just a tiny bit bloated in the bass. If one has a sub to pick up the very lowest frequencies (below 25 to 30hz) so the R900's aren't trying to do something they can't, that's ideal.
I do wish Accessories4Less.com was better about return policies, but if you ask for Mark S he's the owner and a really good guy. Depending upon the situation, he's been known to bend a little. I've bought a fair bit of KEF product from them but because they're the sole dealer for KEF's 'B-stock' and "factory recertified" goods I've never had a problem with anything that made me want to make a return. I've bought a Q200c, a pair of Q300's, a set of Egg powered speakers, a Denon receiver, and more. Everything KEF has been in complete, as-new factory packaging.
I also do have an NAD T758 receiver that I'd bought almost 4 years ago now, and have over the years done the upgrades to make it a full 'v3' version with 4k video, BluOS, and Dolby Atmos. It powers my R500/R200c/R100/R50 5.1.2 system up to reference level in my 13-1/2' x 19' x 7'4" room. I would add a multichannel power amp if I actually listened at reference level, but I never do.