Sky, I'd go for Stubben personally. Both my mares we OK with Albacon (that's what I started them in), but prefer the oval mouth I use right now. You can also look into Mikmar (Mikmar Bit Company
). That's what I use and I believe it's about same price as Stubben (I may be wrong though).
P.S. Both my horses liked Mikmar over KK Ultra. In fact my qh didn't like KK much at all. So if you can borrow to try - fine, but I wouldn't pour the money into one personally.