Does anyone have experience with this beast?  In particular using the drain system.  Didn't go too smooth!

I'm an old pro with the uniflo- this new monster is difficult to operate, and come with minimal instructions.

I'm not sure what problem you were having....  raise the handle to dispense a charge, but then leave the handle up.  Depress the lock pin, remove the metering insert, install the drain insert, and lower the handle, aiming the drain into the powder container.  All the powder will drain out.  When empty, remove the drain, and re-install the metering insert.

if you try and swap metering inserts with the handle in the down position, well...  you're gonna make a mess  

Thanks- I think maybe it's just a matter of polishing/smoothing some parts- the drain and metering assemblies are rough and difficult to switch.

I expect you are right.

The quick-change powder measure is the latest and greatest from RCBS.