I've "tested" the feature to add an Install Package on 5 groups, all 10 or fewer PCs. I did not hear back from the users with complaints nor did out helpdesk. Also, the install looked to be successful per SEPM and spot checking a few PCs.
For RU6, because I badly want to use the app and device control policy, which was broke for me in RU5, I plan to use this feature almost exclusively. My only concern is for our locations overseas. Our SEPMs are in the U.S. and I don't want to bury the lines. I may go the route of SCCM for overseas.
I guess my question would be would our GUPs act as the distro point? I always thought when using this feature, it was strictly the SEPMs that pushed out the package and the GUPs were only for LUs.