Keton's VH in my X1, Sd1+,XD9,SD5, MidJay, were all quirky and never performed properly.....
they are very temperamental. But, when they worked it sounded fine....programming & setting it up with song setups is the difficult part. KORG TC Helicon is a breeze to use and sounds fantastic...
Yamaha VH1 & VH2 still needs alot of help although at this time I have finally come up with settings after lots of extensive tweaking that makes VH2 usable to a point on my S950, Tyros4/5.