Curious as to what others are using for input. Right now I am attempting to play with my PS3 controller but that makes holds and simultaneous button presses almost impossible (at least with how I use the controller).
The only way I've thought of handling holds and simultaneous presses so far is use a keyboard, but that just feels wrong :(

Actually, it is possible to use PS3 controller to play, but only 4 button scores.At first i played like this:
with right middle finger I click on ○, right index finger on × , the left middle finger on △ and the left index finger on □.
But now i'm using keyboard with this configuration:
"/" ○
"." ×
"x" □
"z" △
"c"/"LShift" Left Slide
","/"RShift" Right Slide
It easier and more accurate than controller, just set keys in this order:
Lslide △ □ × ○ Rslide

Had a feeling others were using keyboards or some sort of arcade controller. Having my fingers on all the buttons at the same time feels like cheating after using a controller for so long; but after seeing the difficulty of most of these scores it's probably the only way to do it.

I use this configuration
J=Circle
H=X
F=Square
D=Triangle
S=Left Arrow
K=Right Arrow