I first used keyboard because I didn't know how to get my controller to work. After I 1cc'd all the normals for all the Windows Touhous (And lotus land), I was stumped with 1ccing SA. I just couldn't do it (on normal, I didn't want to try easy). I mean, I couldn't even get past Orin on my first credit.
So then I finally got my ps3 controller to work, and as soon as I did, I 1cc'd SA with an extra life left on my first try. I thought my Touhou skills suddenly were god.
But...For some reason, when I tried using a controller for the other touhous, I did worse, not better. I fiddled with the sensativty and whatnot, but no dice, controller = suck mode. Eventually I got better and better, and could 1cc all the hards (except SA again, I haven't really tried yet though, scared lol, UFO doesn't count either since that didn't come out until after I set my personal goal for beating all the Touhou's on lunatic), as well as a few lunatics. But every time I tried the controller, normal mode was a struggle.
Every time I try a new shooter game for the first time, I try with and without the controller, and keyboard always wins for me.
I WOULD like to try a stick though. I have a very bad habit of moving more than I intend to using both a gamepad and the keyboard. I rekon a stick would help in that department (especially with rapid direction-changing slight diagonals).