From my limited experiments, the 2.6 kernels are OK if you use the LD_ASSUME_KERNEL workaround as stated in various threads on the Jackit newsgroup, and the LSM as also pointed out here. But unless there is a need for hardware compatibility purposes, there doesn't seem to be a real advantage at this point to upgrading. You won't get noticeably better latency anyway, and you will spend time that could be used for making music !
