Installed two days ago on a 1.5 million post VB. Works like a charm.
On our database server (dual AMD 2400MP system, 3 gigabytes RAM) we're seeing a load of about .25 during peak now (12.5% load). Used to be about .50. I was more concerned with overall response time, not load, and this has helped with both.
Our front end system (dual AMD 2800MP system, 4 gigabytes RAM) still has a crap load, 1.50 - 2.50 and that's the one regret I have with moving from VB 2.x to VB 3.x. Our front end server used to run about a .75 to 1.5 load.