Unfortunately, not everything is perfect with the
Catalyst for Wii Remote with MotionPlus. For the most part, the sleeve works as advertised with the standard first-party Wii-mote. I had some issues feeling for the buttons, especially the (+), (-) and Home buttons. This was due mainly because of how thick the material was and the hole cut away from the sleeve to access these buttons was deeper than my fingers were used to. Thankfully, these buttons aren't the most used.
When I had problems with the Catalyst was when I wanted to use other hardware with it - most notably, the Nyko Wand. As the most prominent alternative to Nintendo's controller, it would have been nice if the sleeve fitted the Wand as well as it does the Wii-mote. Instead, the slightly bigger design of the third-party controller means that the Wand simply doesn't make it all the way in. Along the same lines, I use Nyko's Charge Station on my Wii-mote. As a result, not only does the sleeve cover up the charging contacts (though that was to be expected), but the padded battery cover that comes with the Charge Station makes the act of zipping and snapping the sleeve closed nigh-impossible.
I really can't fault the Catalyst too much for the issues between it and my the Nyko Charge Station; pretty much any rechargeable solution for the Wii-motes will have the same problems and each solution puts those contacts in different places. Its incompatibility with the Wand, on the other hand, is hard to forgive.
If you stick with the first-party hardware, the Catalyst for Wii Remote with MotionPlus is a solid product to help protect your Wii-mote from getting scratched up. What it won't do as well as the rubberized sleeves is protect the controller if you drop or throw it; this material isn't designed to absorb a lot of shock. On the other hand, if you are looking for a sleeve that doesn't look like everyone else's and you suffer from sweaty palms, then the Catalyst is probably the product you have been looking for.