Overall Look and Feel of the Picture
I've had my own, brand new RS20 here for 3 weeks and already almost 100 hours of use. It is exceptional. Skin tones are excellent (but not the very best), as is the overall picture. The RS10 was still here, until last week, so I did do some switching back and forth. While the image on the calibrated RS10 is a touch warmer, and a couple of the primary and secondary colors a bit oversaturated, it comes very close to the RS20. It's the black level performance that set these two apart. Watch a bright scene and they look pretty much the same in quality. Kick on a dark scene, and the RS20 really shines, like no other.
I have noted one minor flaw with both of these projectors. For some reason, every once in a long while, the JVCs can exhibit some artifacts when encountering some moderate panning. I suspect it only occurs when the panning is at a particular rate, that just causes minor issues with the image processing. Well, no projectors are perfect, and they all exhibit artifacts in one situation or another. This flaw is very minor, and if it is your only complaint, you will be a truly happy owner.
I have noted one minor flaw with both of these projectors. For some reason, every once in a long while, the JVCs can exhibit some artifacts when encountering some moderate panning. I suspect it only occurs when the panning is at a particular rate, that just causes minor issues with the image processing. Well, no projectors are perfect, and they all exhibit artifacts in one situation or another. This flaw is very minor, and if it is your only complaint, you will be a truly happy owner.
Bottom Line in terms of image quality
Easy, the JVC RS10 does a great job, at just about everything, and the JVC RS20, just does it all, just a bit better.
JVC RS10, RS20 Projector Performance
Projector Brightness
Tie! Both projectors are endowed with plenty of lumens in their best modes. After calibration, they were almost identical, with the RS20, surprisingly just slightly beating out the RS10 with 775 lumens compared to 740 (that's barely a perceptable difference). I say surprising, because last year's RS1 (about the same brightness as the RS10, was dramatically brighter than the RS2. (I had considered buying an RS2, but it wasn't bright enough for my 128" screen.)
The RS20, and therefore, also the RS10, have sufficient brightness, that I partially close down the manual iris when filling my large Firehawk G3.
When it comes to maximum lumens for HDTV and sports, again, the two projectors are almost identical, with the RS20 coming in at 844 lumens compared to 814. For you large screen users like me, that is enough to tackle sports and TV with modest amounts of ambient light, and still look great.
What about sharpness
No projectors are perfect, and if I had to answer the question of what these JVC projectors' biggest weakness is, I would have to say, that that merely having "average sharpness" is it.
Yes, sadly, it is true: The JVC RS10 and RS20 are only average in sharpness among the 1080p projectors. The good news is that, while some other projectors are visibly slightly sharper, there's nothing wrong with either of these. Unless you have seen either, side-by-side with the few projectors that are exceptional (the InFocus IN83 comes to mind) in terms of sharpness, you should be perfectly happy. I sit very close (11.5 feet) to my large screen, and have excellent vision. I know there could be a bit more sharpness, but I'm never sitting there thinking - "this looks soft" or "this doesn't look really sharp". I am sufficiently pleased with the sharpness of either of these JVCs. Since we are comparing these two projectors here, let's just say, both exhibit identical sharpness.