I haven't had the need to disassemble it for cleaning so I use a small brush to remove crumbs and stuff. Sometimes I too feel that it is large, but still the numpad is convenient. The alternative would be a 'compact' design but I don't like how they cram the Enter key in a single row and make the up and down keys half of the height of a normal key.
My complain against it is its privative nature - with Linux, you can't use the screen brightness keys unless you install something like Logiops or Solaar. Alas I've found Logips a bit buggy so when you're running it the mouse wheel becomes really glitchy so you have to restart it.
I'd like it to have one of these wheels some keyboards have to control volume or something else, a second Meta key and that one could make it so when powering it up it started with no backlight.