There have been threads over on Gateway to Airguns'
China Gate, including
this one about the Ruger.
It seems that there is nothing necessarily wrong with the Ruger Air Hawk, it's basically a Chinese copy of the RWS/Diana model 34, so it's not really a Ruger.
I own an RWS/Diana 34 and have been very happy with it. If you've got the money most people I know would suggest getting the 34 over the Air Hawk. Digging a little bit online you can find the 34 for ~$175, give
Umarex a call and you can get a refurbished 34 in the neighborhood of $140.
Clark