I just did a quick comparison against poclbm for me.

On my dedicated 5870:
poclbm     SDK 2.1: ~424
phatk       SDK 2.1: <420
phatk imp SDK 2.1: ~432

poclbm     SDK 2.4: <424
phatk       SDK 2.4: ~424
phatk imp SDK 2.4: ~437

So on SDK 2.1 your improvements made it so phatk was better than poclbm in 2.1, and way better in 2.4.

The init optimizations gave me a minor boost of ~0.5 MHs over 2011-07-11.