i quite like dxTop so far. the screen organization is just pure genius: one extra screen AND less swiping!
the dock is also great...i put all my toggle widgets there (mute all, bluetooth, wifi, etc) and it freed up a bunch of screen space.
the way icon options work (long press then immediately drop) are also very useful and make the droid feel more like a computer, which i love.
finally, i like that dxTop is "lightweight", meaning that it doesn't try to change Android's overall look and feel very much.
things i'm not sure about yet: not really sure i'm gonna get a whole lot of use of the 2nd tab at the bottom and it makes it harder to get at the apps tab. also, i have come back from unlock several times with a force close, but if i ignore it, there appear to be no ill effects...weird and annoying.