I've received a loaner review unit. Yes, it's heavy. When I read that the block on top was glass, I thought "You have to be kidding" but seriously, it's a solid block of glass with two holes for the tubes. I'll have to spend some time with it but my initial impressions of the sound are that is relaxed and a bit warm, typical of my experience with Sovtek tubes.
How long is your loaner unit? Guess you know what I may be asking, if it's not too much trouble.