Have heard La Source today at Audiophile Club, London. I own AA Capitole Reference SE and had demoed it 6 months ago in the same setup at Audiophile Club, so can try to make a few comparison remarks. The rest of the setup was BC-Acoustique A4 speakers and AA monoblocks; La Source was used as CD Player & Pre-amp. I had a 30th ANNIVERSARY SAMPLER CD with me which I used during the audition (amongst others).
La Source was so easy to listen to with all material thrown at it. It truly draws you into the listening - you are curious to hear more and more.
Soundstage depth was awesome & that was one of the main improvements over the Capitole Ref SE. There was so much more space beyond the speakers / listening room boundaries - it was scary. A large orchestra hall was easily imaginable.
Clarity of the presentation was phenomenal: strings very taut, zero distortion, ie very real.
High frequencies reproduction was spot on - very detailed, airy and very real once again. BC-acoustique speakers posed no bottlenecks in this area, so helped to hear La Source potential. Capitole Ref SE had also been very good in this area, although perhaps lacked a sense of realism just a tad.
Bass reproduction (eg church organ) has been top notch, perhaps not as thunderous as I heard in other reference setups, however, that could be due to AMP/Speaker limitations.
I was told that the Transport is custom & top of the range Esoteric unit. The player looked like a monolith unit certainly a bulletproof piece of engineering, weighing some 25kg.
When comparing the two AA players, of course, one can feel a similar AA sound signature, La Sources being a clear winner in all areas. However, not being able to afford a phenomenally higher price level of La Source, I'd say I can very happily live with Capitole Ref SE unit!
If you have that extra cash at your disposal, by all means consider La Source in your setup! I would at least love to hear its potential in other Reference AMP/Speaker setups...