The BenQ is extremely sharp, and fits perfectly in our "sharper still" classification, while the Epson, though not bad at all, fits into the "average" category. Those are the only two categories we use for 1080p projectors. You'll notice any sharpness differences more on pure digital content, say HDTV, than a movie (other than animations). The BenQ W5000 is stunningly sharp on all that great digital programming on channels like Discovery HD, not to mention sports broadcasts in 1080i. (Remember some HDTV channels are using 720p, thus not as sharp.)
A clear win for BenQ, but you only get to truly appreciate the difference if you have had a chance to view an average projector side by side with one of the "sharper still" projectors.
I'll put it this way, since I am constantly playing with projectors in both sharpness categories: For movie viewing I don't consider the difference between a good "average" sharpness projector like the Epson, and a "sharper still" like the BenQ to be an important issue at all.
Knowing, however, how sharp the BenQ looks on that Discovery HD and other top quality digital content over 1080 HD, I would say that I would appreciate the difference between BenQ and the Epson (or my similarlly sharp JVC), and occasionally long for that touch of extra sharpness.
In other words, with a projector like the Epson, the vast majority should be perfectly happy with its sharpness, as you won't miss that little extra, that you've never seen. Pixel convergence is a key reason the 3 panel LCDs aren't as sharp as the single chip DLPs. There is variation among the Epsons but misconvergence is always easy to see if you are standing near your screen. At normal seating distances, you shouldn't notice separating colors, but it does add that bit of softness.
On film you would barely notice the difference, but on all digital content, like Discovery HD, the BenQ will be immediately and visibly sharper, in a side by side comparison.
Creative Frame Interpolation
Epson's got creative frame interpolation (CFI) and it's their second generation. the BenQ does not. Epson's current iteration of their CFI, works very well with 30/60 source material, but I'm still not sold on its performance with 24fps content typical of movies on Blu-ray disc. This year's implementation is smoother on movies than last years' projector, and close to the Panasonic in performance (theirs may be the smoothest).
The Epson system now converts 24fps to 96 with CFI rather than trying for 24 to 120 like it did last year. It also knows when to quit... If it starts getting overwhelmed it can now turn off (briefly) it's CFI functions. That makes sense.
Imagine trying to smooth all the fast motion in the Bourne movies, especially the last two, where the camera itself appears to almost never stop moving, and when it does it's a second or two here, and another second 15 minutes later... In other words, the effect is constant movement, by every object in the scene. Even if a CFI could remove the motion blur, you'd end up with the same movie, as if the cameras were all now stationary. I assure you, that the director of Bourne would not be happy, after he went to all that trouble to create the effect, for you to remove the dominent visual trait of those movies.
The BenQ does support simple frame interpolation taking 24fps to at least 48 fps, (2:2) with no creative frames.
The Epson offers a dynamic sharpening feature called Super-Res. It works, but ultimately, the BenQ is still a touch sharper. The more you turn up Super-Res, the more likely you'll start spotting some of the "trade-offs" the less desireable artifacts that are the result of the sharpening. This is typical. Remember the old saying: "All things in moderation!" That works particularly well when using dynamic features.