This ROM from the start seems MUCH more "snappier" than the JK2 Eugene put out.
But, I'm still on the fence regarding Battery Life on JK6 vs JK2.
I am testing, but I noticed From a full charge then unplugged overnight (7hours) with only Gmail+Contacts Synching, I went from 100-89% using JK6. When I was using JK2 I went from 100-98% overnight.
Some of the cause could have been from some of the additional bloatware I found running in "Services" on JK6 for me, under Application in Settings, like Slacker Radio, so I will compare again tonight.
On another note, I've also been comparing using Power Tutor, which isn't for Galaxy S phones at the moment, but it does give a lot more detail than the stock Battery Usage app. I found that with the screen off on JK6, there is only a 3-7mw drain. On JK2, that was more like 25mw.
With the screen on lowest brightness, (auto-brightness off). I saw around 400-425mw on both. It's interesting to note that the light sensor draws about 100mw, according to Power Tutor...
Again, all this is up for discussion, especially since Power Tutor is not optimized for the Galaxy S...