Knaithrover -- Great idea to start a KEF Q-300 owners' club! The Q-300s came out in a blaze of publicity in 2011, but since then seem to have been almost completely upstaged by the Dali Zensor 3, Q Acoustics Concept 20 and now the lastest iteration of the B&W 685. They rarely get a mention in these parts nowadays, so it's great to see someone coming on the board and singing their praises!
I bought my Q-300s a couple of years ago and have them hooked up to an Arcam A18 amp and Cambridge Audio 651 CD player.
I more or less totally endorse your comments about the Q-300s. Having listened to a couple of different speakers (MA BX2 and B&W685) at an in-store demo, the first thing that struck me about the Q-300s was their amazing imaging, soundstage and dynamic presentation. The vocals and instruments were brilliantly separated and each strand of the music seemed to occupy its own space. Obviously, you can only tell so much from an hour in a hi-fi shop, but the KEFs seemed so much more detailed and engaging than any of the other speakers I auditioned.
Having lived with them for a couple of years now, I can honestly say they have revolutionised the way I listen to music. I am now completely absorbed by music as a 'performance' rather than just listening to something almost as 'background'. My new system is more critical than my old 1980s system (NAD 3020, B&W DM110, Denon 520CD) and less forgiving of bad recordings, but it has revitalised my love of music.
Downsides? Well they are budget speakers and no speaker is perfect. I think all of that engaging crispness, mid-range detail and dynamics comes at the cost of a slightly thin, clinical and sharp top-end. This varies from recording to recording. Modern, digitally-recorded stuff is generally OK. Some older, remastered analogue recordings have a tendency on my system to sound a little thin in the treble, especially sibilances. The bass on the Q-300s is very impressive. Like you say, it has real depth and scale to it. Sometimes I think the speakers need a good, solid bass guitar on the recording to 'kickstart' the bass and provoke that great, room-filling bottom-end response and balance out the sound. I suppose what I'm saying is, sometimes the speakers lack a little natural warmth in the lower-mid range and until a well-recorded bass instrument enters the mix the mid-range can sound slightly toppy.
These are minor reservations, though, and I'm aware that it may be a system issue rather than just my speakers. KEF Q300s rock! For the money, they provide bags of dynamics, a truly impressive soundtage and incredible imaging. On a limited budget, they have really opened my eyes to what hi-fi is 'capable of', and how absorbing and immersive listening to music at home can be. For what it's worth, I think the NAD / Q-300 combo should be ideal. The smooth top-end of the NAD and punchy bass will suit the KEFs down to the ground. Enjoy!