I owned them both at one time, the Pioneer version as well the HD350.
It's strictly based on memory and individual models, so YMMV.
My recollection is the RS2 clone seems to have better contrast but less bright while the HD350 is a tad sharper.
Physically the RS2 has the outputs in the back, not on the side.
In terms of noise, the newer model is definitely quieter, noticeable but not drastic.
The vertical and horizon adjustment on the RS2 is mechanical while the HD350 is electronically controlled. I found the mechanical lens door opening sounds (like a Sanyo z4000) like scraping sandpaper. Ugh!
Unless you put them side by side, it's a toss up. Your room environment would also affect the contrast.
I'll pick the one with the lesser usage, the Pioneer in this case though it's older. If they are the same vintage, go for the HD350. Brightness matters more to me.