Ive been doing some testing of different controllers to use with leap, and will share my thoughts here. Basically to save anyone else who wants to use leap the time and money.
First, I went super cheap, and bought two of these cheap things. https://www.amazon.com/gp/aw/d/B01M69UO10/ref=mp_s_a_1_11?ie=UTF8&qid=1508673010&sr=8-11&pi=AC_SX236_SY340_FMwebp_QL65&keywords=vr+gamepad
Surprisingly, they work ok but lack a touchpad and trigger button, so not practical. I stuck two together like this, to get the extra buttons and the result was a surprisingly good vr controller. The joystick axes are good.
Next I tried the vrcase, which is a good shape but the joystick is awful, buttons are squishy and hard to reach. It disconnects if left alone and steamvr needs restarting to get it back.
Finally, the magicsee r1, which is far superior in almost every respect, comfortable, good buttons, has the best leap tracking because of its size, connects instantly and stays connected...
So yeah R1 by a landslide. Even feels like you are holding touch controllers. I will get a 2nd one and ditch the vrcase, and advise anyone to do the same. I am not working for magicsee but if they want to give me money for this please do.
If anyone has tried other controllers please share your thoughts.
Edit: got a second one and this controller is definitely the best for Leap as far as I can tell.