I blew $90 on a biscuit joiner jig that didn't fit any project I had

Bought a biscuit joiner jig about 4 months ago thinking it would speed up my face frame work on a set of oak cabinets for a client in Dayton. Got it home and the fence wouldn't line up square on anything wider than 8 inches, so I ended up shimming it with playing cards just to make it usable. Between the $90 and the two evenings I lost fiddling with it, I should have just kept cutting my own splines on the table saw like I always did. The worst part was the client noticed the gap on one stile and I had to redo the whole door. Has anyone found a jig that actually stays true on big frames, or am I better off going back to a router and a slot cutter?