In December of '06 I wrote a long email to Pfhorrest listing various feedback pertaining to this scenario and he responded to it point-by-point. I completely forgot about it for over a year due to being distracted with school and other problems, but I really should really should respond to it now that this thread reminded me of it. I'll do it soon, assuming I don't forget again (I have a terrible short-term memory, but as this thread looks unlikely to die anytime soon I probably won't forget).
Eternal X manages to capture the feel of the original trilogy, I feel, better than any other scenario released to date. The main thing that keeps me from ranking it higher than Rubicon X is the same quibble I had with Infinity when first playing it (as well as Chrono Cross, which isn't related to but is nonetheless worth noting) - namely, that it's difficult to follow the sequence of events, though that's probably a direct consequence of its nonlinearity, as well as the complexity of its plot. The Story page solves this trouble for Infinity - if one is confused about matters, one can simply refer to terminals from previous levels to review text one has already forgotten. It would probably help players' comprehension of Eternal if someone posted the terminal text somewhere, just because there are so many plot strands to keep track of that one naturally loses track of details mentioned in the past, especially if one doesn't have the time to play the whole thing in a short burst (as I didn't).