I am not an experienced reviewer, so consider this simply a bunch of comments on my new X5 speakers. My comments are complicated because I purchased a pair on 45 tube amps a few weeks before getting the X5s, so my current sound is quite different from where it was a couple of months ago and I cannot always say which change is due to the amps and which to the X5s. I fell in love with the Spatial Audio sound at an RMAF a few years back, and have owned M3 Turbo S and M3 Triode Master speakers. But as soon as I fired up the X5s it was obvious that these were a noticeable improvement. Hard to explain, but I get a feeling of solidity to the soundstage that was not there before. I keep telling my friends it's as if the music were rooted in a huge stage of marble. There is now a review of the Spatial Audio X2 in the latest Absolute Sound and in it he uses the same word that I was using – clarity. This morning I was listening to the 1st cut on Spirit's The 12 Dreams of Dr Sardonicus – a song I have listened to many times since it came out around 50 years ago. For the first time I heard the phrase F**k It in the right channel at little less than 2 minutes into the song. My jaw dropped. And the recording venue of each piece is really noticeable – the soundstage switches from huge to small and back as the songs change. As for the bass from the 12” subwoofer on the speaker, it is quite good, but I am also using a pair of GR Research's Dual 12” servo OB subs controlled by a DSpeaker dsp unit (This is why I didnt get the X3s). I can switch these subs in and out of the signal – this shows they play a bit lower than the sub on the X5, but on most of the rock that makes up my music collection, that is seldom an issue. Since these are a couple of dB more efficient than the M3TMs, a slight hum showed itself and it took me several days to isolate and eliminate it – a trade-off in the efficiency wars. And while it isn't necessarily an indicator of better sound, the build quality of the X5s is in another league. They look fabulous and expensive. Even without the furnished spikes installed, these are very stable and barely wiggle if you push on the top front. I have built a bunch of speakers and I could never duplicate these. Overall, these are highly recommended and may well be my last pair of speakers ( I just turned 73). And by the way, my M3TM speakers are now for sale on the trading post.