I have the trial version and am happy with the results. The only thing holding me back is the enormous number of page faults for the BsMailProxy, BsFire and BsFileScan services - which a run under one process. I have 4GB of memory and a 4GB page file. I run very few processes concurrently.
I have a Dell laptop with Intel Core2 Duo CPU T7500 @2.20GHz.
The process in question has, since boot-up this morning, had 19,795,000 page faults! It service's memory size(Private Memory Workinh Set) is only 208K. That many faults has a dectectable hit on performance, not to mention thrashing the disk.