I've been using Jaguar for a while now, and the new "Aqua drop" is beautiful. It rarely shows up though, because Jaguar is so fast and efficient, even at this early build. The "Aqua drop" is, like all the other GUI's, rendered by the GPU in QE. It's really cool to be able to minimize a playing video in Quicktime without losing a frame... But i haven't noticed any window-resizing speed-up. It maybe because of my slow gfx-card, but who knows. Everything seems to be faster at a lower resolution, and since I've got a GF2MX it makes sense. The card is slower at high resolutions like 1280x1024 and above.
What I really love about Jaguar is the scrolling improvement. Scrolling in e.g. IE is about the same as in OS 9 now.