I've got one and love it.
Mounted long on a full length handguard while standing shoulders squared up to target (isosceles) leaves my support arm just slightly bent, very quick and stable on transitions from target to target.
I would not recommend it mounted short on a carbine length handguard, the angle would be uncomfortable and its not really the way it was designed to be used.
Magpul's Travis Haley's grip, tried it and it works well for me.
YMMV for me as well...................I had to look up what it meant first