@voodoohao - It may depend what you listen to. I have a positive regard for Jan Meier's work; some others don't.
There's a "rule of thumb" the LCD2 needs 2W (peak? rms?) to deliver its best. I don't know what this is based on exactly; call it the wisdom (or the delusion) of crowds if you like. Concerto can deliver 2W peak into rev 1, about 1.8W into rev 2, given a 4V input. However, the StageDAC delivers 2.2V rms or a little over 3V peak. With 8dB gain (2.5 x), we're talking 1W peaks or slightly more, dependent on rev.
To be sensible these figures, while short of the 2W rule, would yield ear-shattering SPL levels. On most of the material I listen to the Concerto is more than enough. Perhaps if you listen to a lot of orchestral (high dynamic range) material, it may not be - IDK, I listen to that kind of material on my speaker rig! I have gained the impression some feel power is needed - think Schiit Lyr territory - to get satisfactory "kick" and "slam" in the bass/sub-bass. I confess the reasoning escapes me, and I can't hear this difference [see my sig!], but it may be true.
It seems to me Jan Meier values neutrality and clean sound. The Concerto (and Stagedac) certainly achieve this. That means it gets really close to getting out of the way of the music, adding little or no excitement or euphony. Compared to the Schitt Lyr with suitable tubes, for example, the Concerto can sound a little dry in the lower mids.
It 'compensates' for this - if compensation is needed - with deep blackground and terrific attack throughout. Added to this it is highly detailed and has extended, nice highs (slightly sweet, as Skylab remarked).
Personally, I wouldn't hesitate. The combo functions as a reference point for me - whatever else I get, I hope/plan to hold on to this (or possibly the Stagedac/Classic) combo for a while. But that's just me.
I am sure others will chime in with opposing views, which will help you get a balanced (
) picture.