My first really good edges came from a Lansky. I subsequently tried the GATCO guided system, and was able to get very good edges from that. Both systems illustrated, to me, what a really clean, uniform bevel can do for cutting performance. That spurred my interest in developing my freehand technique, with which I've been spending a lot of time lately, using diamond hones from DMT. I've also been experimenting with sandpaper on soft & hard backing, producing some nice convex edges. Having said all that, I still think guided sharpeners have their place. I've even recently ordered a DMT Aligner Clamp & Magna-Guide hone holder, with which I'll do some experimenting on bench stones and Dia-Folds.
I'll never stop working on improving my freehand skills. I find it very relaxing & therapeutic anyway; it's very satisfying. But, there are times when a guided setup will be very much appreciated (quick restoration of edges on kitchen knives, for instance).