I have no problem with people who ride them, and it's their choice, but:
IMO they look stupid.
To me it feels like there isn't really a bike there, as if I'm on top of the bike instead of 'in' the bike.
They are theoretically slightly weaker.
I'm 6' which isn't particularly tall, but I cannot sit comfortably on a Total Hangover Frame, even when I'm stopped and my feet are on the floor.
They only 'help' with one trick (Whips).
I really don't see how a 7" standover would make any difference for whips at all compared to an 8" high frame.
So many good riders have high standovers and high seats and have no problems with whips for example:
Drew Bezanson
Morgan Wade
Dean Cueson
Dennis Enarson
Stevie Churchill
Scotty Cranmer
and so on.
Joe Johnson was landing Double Whips and getting over triples I believe back in the early 90s when seats where super high.
Like I said I don't hate riders that ride them, but I really don't see the point, especially when they only benefit one trick. If you really want one get one.