Ok: Lich
Unfun: Emberwraith
Gargs Ravenous Drive needs some changes, as you can see in the replay:
Part 1: Inn Lane
Testing it against creeps, against my opinion it works fine against them.
Part 2: Bottom Lane ( The fun part )
I tried to grab Swashy and BP. Works on swashy most of the time, I even managed to throw him into the water, resulting in a helpless Ai until I tried to grab him again, where he blinked over half of the screen.

I think I never got to grab the BP, maybe his collision size is too big so he gets pushed away too far and can't be grabbed.
Part 3: Mid Lane
Tried to grab the RK several times, didn't work.
Result:
You can make people stuck on water ( not talking about getting them ontop of a cliff where they cant escape without blink

Some heroes are very hard to grab, maybe even impossible.
Increase grab range for heroes or don't push them so far away.