They feel really solid. I would say their feel is on par with what the vanilla shells are.

My biggest concern when I finished was if the HD rumble would be effected, or the noise they made. I tested out the HD rumble with several games a d with the Labo keyboard and the HD rumble works just as well!

The biggest thing to keep in mind when doing it is to file down these points in the plastic http://imgur.com/gallery/d1QFdL7

Basstop still doesn't quite have the molding precise for the joycons, but they are a lot better than they used to be. You need to file down the plastic at these points or else when you try to screw the joy cons shut they won't be entirely flush on the side of the rail towards the faceplate.