Rob Steibel just posted a bit of a conversation he had with another Jack Kirby fan about how a reprint can alter how a comic is printed. The two big issues were with art that's been "touched up" or even re-drawn and, more noticeably, recolored. Steibel then posted several sample pages scanned from an original copy of Fantastic Four #5.
Me, being the curious FF fan that I am, decided to track some things down for comparison. Not surprisingly, the originals have the biggest issues with mis-registration and dot-gain, not to mention that at a half-century on, the pages themselves have become discolored. The two comparisons panels I was able to get a hold of fairly quickly were the digital version currently available on comixology, and the earlier scans Steibel had posted that, I believe, came from the Marvel Masterworks series.
I'll let you judge for yourself which you like best. From left to right, these are the original, the current digital edition, and the Masterworks reprint...
Given that Jack Kirby wasn't really concerned about inking, and was okay with someone like Vince Colletta taking vast shortcuts by erasing whole figures, provided the main characters for any given scene were still present, I don't think he would've minded too much about some of the finer details getting lost over time. Though, to the original point, and speaking as Kirby enthusiast myself, I do appreciate being able to see something closer to his original work.