New McIntosh 462 amplifier -

Yes. Had it for about 2 weeks. Still breaking in So difficult to assess yet. Preliminarily though, it is well built, absolutely noiseless in operation and very cool in its operating temp. Too early to tell how much improved over very reliable 452  predecessor unit but VERY satisfied out of box operation with performance at least as good as 452 and pre-break-in indicators are sonic improvements are very likely. 

I was astonished as to how good my new Mac mc462 sounded right out of the shipping carton.  This is at least in part due to several improvements in the unit when compared to the MC 452,  resulting  in a 66% increase in dynamic headroom, among other things (check the Mac website).
The Amp has complete control of my Harbeth 40.2 speakers resulting in the best bass and clarity I have ever heard from my Harbeth 40.2 speakers ( I previously used a PS audio amp and a pass 250.8 amp with these speakers.)

I talked to a McIntyre support person soon after I purchased my MC 462 and was informed that there is no break-in required for the Amp to achieve its maximum performance due At least in part to the quad balanced design and the auto formers.