Without Seeing Your Room.....
I have done side by side comparisons of the JVC RS1 & the Epson Powerlight Pro. I'm an A/V integrator and wanted to see the difference. I really liked both products but ended up going with Epson for an under $10K projector line (I'm a former Vidikron dealer and have become underwhelmed with what they are now offering).
Epson $4K VS. JVC $6.3K: From a "value" stand point, the Epson is brighter, carries a 3 year warranty, comes with an extra bulb, comes with a mount, and retails for $2,300 under the JVC. Tough to beat. The Epson picture in comparison to the JVC is a little softer. I did not notice any type of screen-door effect on the Epson. As far as color goes, in a totally dark room the JVC looked great and a little better than the Epson, but not by much. Up the dimmer switch on the lights and the Epson picture was stronger (still not going to do well in a fully lit environment). The JVC really really needs a light controlled room for it to WOW you. I have read in various forums where some people have complained as to what analogue sources look like on the JVC. I did not notice anything out of the ordinary when I was viewing it. Historically, DILA white uniformity is an issue in test patterns but that's not typically applicable to regular viewing.
Both of these projectors provided a really good picture for the price point (< $10K). I think that if someone either had never owned a projector before, had to have 1080P, and/or had a legacy piece they wanted to upgrade either one would blow them away. So, to answer your question (and mine since I wanted to know which to recommend to my clients): In my eyes, the Epson is the better value without doubt.
As far as DLP goes: I think that accross the board under $8K-$10K LCD & DILA offer better value. Just personal experience. The only under $10K DLP projecter I've ever really fell in love with was a Projection Design Action! Model Two ($6,500 msrp). On paper, it makes you yawn. On the screen, WoW!
Note: The Epson will absolutely NOT do well on a perf screen. I tried both projectors on a plain white screen & on a white perf screen. The JVC did well but the Epson was unbearable.
Note2: I have never heard of or read about LCD longevity or unusual durability issues with Epson projectors. But, since I strongly believe in the fact that "I don't know what I don't know", could someone please link an artical or website documenting these issues. This information would be extremely valuable to me. Epson makes nearly all of the LCD panels found in projectors and televisions and it would be interesting to read about any re-occuring problems with LCD technology based products and Epson pannels.
Thanks!