If you are using Microsoft Exchange then this is a MUST tool. Version 2.1 just makes it's better with the ability to run a Health Check AND a Performance Check!
When you select a Health/Performance Check, ExBPA will do the "normal " health check, but it will then take 240 performance monitor samples every 30 second (So the whole scan will last over 2hours)
Once complete, it will then compare the samples it collected against the Troubleshooting Exchange Server 2003 Performance whitepaper and make recommendations. This is truely a major step in the right direction for an Exchange Self Help tool!
Go download Build 2.1.7599.0 NOW! from http://www.microsoft.com/downloads/details.aspx?familyid=dbab201f-4bee-4943-ac22-e2ddbd258df3&displaylang=en