I've been on 2 Stand Ups.
Riddlers @ SFMM
Vortex @ Great America
Out of those Two, Riddlers is better by far.
It's smooth, forceful, has a little airtime and is definitely rerideable.
Vortex just needs a good retracking because it could be a really good ride.
But right now, Its the roughest ride in Great America.
I'll get to ride Mantis this summer, So I'll see how that is.