I don't know if this helps anyone, but I was having horrible lag problems when I did the initial install. I was going to give up and go back to BB 1.1, so I went into recovery and wiped data and cache, but when I reloaded my backup I accidentally loaded the backup I had just done. The good news is that on reboot all my lag issues were gone and the speeds were back where they should be.
I also had major lag issues. In the Froyo release thread they recommended me to check what my clock speed was, turned out it had defaulted to 250MHz instead of the droid's normal 550Mhz.
I installed an overclocking kernel and SetCPU is available on xda developers' forums. Set myself between 400 and 700 MHz and the speed is back to normal, although it feels the same as stock 2.1, not insanely faster like everyone has made it out to be.