Is "software update" in a working state yet?

[Jeff Molofee]

I've noticed software update pop up on the screen quite a bit lately.  
Initially it popped up and did nothing.  Now in 8.1-RC2 it pops up and 
shows me that I actually have updates.  When I click update, it seems 
like it's actually attempting to upgrade the listed packages, but the 
entire process always ends with "command 'update-packages' is not known".

Do I have something misconfigured or is it still incomplete?