The little UV-3R has no harmonic suppression to speak of. When switched to VHF and low power, the second harmonic is as strong as the frequency in the display. Quite horrible. If you want, I can measure one again and send you the spectrum analyzer images by mail.
The UV-5R is actually quite good. More recent batches (firmware versions 251 and later) were even better; about 60dBc down on both bands.
The new Baofeng UV-B5 is fine too. This one has a better front end and low levels of phase noise. As a result the UV-B5's receiver isn't overloaded as easy as the UV-3R or UV-5R. If you live in an RF polluted area and you want something Chinese, this model should be on top of your list.