Wow, the smoking ones are disgusting...
I don't get why people would have machines clogged by having cats though... We have 13 cats (no, I'm not making this up, 13 cats. We live out in the countryside, they have outdoor pens and free access into the house) and in my experience, most of the cat hair sticks to the outside of the case, on the grills over the fans (where you can easily just pull it off and dump in the garbage). Only fine dust gets into the machine, and just blows out with canned air. It does not smell at all, and I don't see why it would...
I guess people who never open their case may have trouble... but I don't clean my machines out very often.