the latest sense 2012 is the fastest 2.5 sense.
It was desiged for our phones, so it is not as taxing on our TP2 processor.
BUT other versions meant for other stronger devices like HD2 also have more features.
With 2012 version Manila/sense and latest build 21899 I was able to feel my unit running as fast as a Sense 2.1 rom..
Tests aside,
I always perceived Silence, MrX, and Malrom the fastest and thats why they are in my sig

EDIT: mayby I shoulda made my sig font bigger