Like most average fans I've only heard "The Gift of Music" and "Moment of Betrayal," and the fact that there's still 120 minutes of music left to hear that could be this good or better has me very, very excited.
Regarding the whole drum production debate, I listened to "Along for the Ride" and "The Gift of Music" back-to-back this morning and I concluded there's a VAST improvement on the drum sound this time. I do like DT12 overall, but the snare sound (especially in the slower tracks where it has room to breathe) is definitely too lifeless for my liking. Not so with these new tracks. While the drum production is certainly less "organic" than when Portnoy was playing/producing, I really like what they've done this time around (and I'm a drummer).