compare it to every non-snapdragon Android phone, and it seems on par or just slightly slower. The Milestone was slower with 2.0.0, it is on par or a bit faster with 2.0.1. The G1 used to be on par in terms of smoothness, in terms of load times, etc, it was slower.
with the newer roms it is smoother, but still slow in terms of non-ui related performance.

iphone is fast, because it doesn't multitask, is pure native code, etc.
the BB is fast, because it is just a simple ui/OS.

webOS has a great architecture, but I agree that faster hardware would be very welcome.

bottom line: Android got fast with fast hardware, and Android is the most comparable.