Agree with others that the controls are challenging. One thing I think might help a lot is "adaptive steering" -- that is, slow down the turning when the ruumba is moving forwards so things don't feel quite so jerky while driving around, but also don't feel sluggish when rotating in place. But this is just begging for gamepad support!
I also wish I had a first-person camera mode where the rotation follows the ruumba.
I think that adding more mass to the containers or friction to the shelves would could help, but maybe the ultra precision required to grab them is intentional.
Editing my dude works really well, I'll have to check out pmetra.