I've used it a lot, as well as other popular toolkits (Qt, GTK, etc.) and I find that wx is, at the very least, the least bad option and overall programming in it hasn't been a pain, regardless of which binding I used.

I guess my only complaint would be that it's a bit harder to do something way outside the norm when compared to Qt, but at that point it might be better to use native SDKs or straight up OpenGL or something for your GUI.