After a week of testing KP49 is completely stable for me, with default, dsp and ideal modes.

The one thing I notice is that even without overclocking, using the media player drains the battery much faster than the stock nokia kernel. Basic use, 25 min of music in the car and on stock today I'm at 92% left (running for 3.5 hours so far). The best I've been at with the same use with KP49 was 75% over the past week using battery graph. I'm running CSSU, 1.3...no fancy patches or crap....just figured I'd share. I didn't personalize any of the KP settings, just ran them as-is.

Other than that battery life with any other task seems on par or better than stock nokia kernel on my device.