After checking around, it sounds like K&N makes a replacement for the air filter that is an improvement.
Even with the few issues on the 16's, I'd still not hesitate to buy one. For reliability the only things that compare is a honda. And it might be a draw there.
The Honda Pioneer SxS has a few issues I'd stay away from. The 4 wheelers, especially the Rancher, is pretty much bullet proof.