Thank you 1Zip.  
The differences are pretty apparent to me, as I owned the amp for 3 years or so before the upgrade, and didn't change anything else in the system afterward.  I'm not sure if a casual listener would appreciate all the differences I heard...
Everything got better.  There were zero trade-offs.  The biggest difference was sweeter highs - a touch more liquid sounding, and a bit less grain.  I didn't really notice any of this before, but when you change it it becomes more obvious.   There's more insight into the recording and better detail.  It's also a bit cleaner sounding.
By far the best $120 I've spent on it.  Far better than the $125 Shunyata Diamondback power cord - which is very good.
The only hard part of it was waiting for the 100 hours of burn in.  Well worth it in the end, but I got a little antsy, as a few others here have.