What are your thoughts on using Unique w/ 180 gr plated X-Treme bullets ?  I'm not looking for a "hot" load, I just want to use them for USPSA matches, so a mild / medium load will do fine.

Unique is a good powder, it places enough powder in the case where double drops are easily seen, depending on the load.
There are newer powders like Power Pistol, BE-86 and the newest being Sport Pistol that may burn cleaner and provide better metering when dispensed from the powder measures.

I have burned lots of Unique in 10mm.  It is one of my "go-to" powders, especially for cast bullets when I don't want full house loads.

I like it for mid power loads with 150-165 grain bullets.

As long as your press meters it properly it is a great powder.

I use it for shooting 180gr cast bullets great results!!!