Very much enjoyed this in rehearsal - although my frame of reference is limited against other 610s - i got it a bit growly pushing the amp a little and notice it has a much more vintage feel and sound to my BT2, but I found it felt a bit "bigger" across the range, and in super lows by comparison I didnt feel it quite had the authority of the BT2 but with super lows I'm talking about a sub - dont get me wrong, it still sounded good but as a direct comparison, that's how it felt.
I'll report back once its gigged in may - the band next door in our rehearsal room complained a little about the bass being too loud in our sound proofed room....