We've discussed this kit - and compared it with the big Revell one - several times in the Forum. (When I did a search on the phrase "Imai Cutty Sark" a minute ago, I was surprised to get more than 200 hits.) The problems with the winches and the booby hatch are covered in this relatively short thread from 2006: /forums/650801/ShowPost.aspx .
Both those problems are easy enough to fix. Slice one end off each cargo winch and swap the parts, so you get one winch with one cable lifter and one winch with none. (A glance at the Campbell plans will show what I'm talking about.) And a few minutes' work with some styrene sheet will fix the booby hatch.
The Imai kit does have a number of points in its favor over the Revell one. The maindeck is, indeed, molded in one piece; the major problem of concealing the joints between fore, midships, and aft sections (one of the bigger challenges of the Revell kit) isn't there. The planking seams, on both the deck and the hull, are, if I remember right, countersunk rather than raised lines. (The countersinking is, perhaps, a little overdone, and the butt joints in the deck aren't right, but a good paint job could make those deck parts look mighty impressive.) The paneling on the sides of the deckhouses is much better represented in the Imai kit. (Imai shows the panels in pretty accurate relief; Revell just makes raised lines around them.) And Imai, if I remember right, represents at least some of the carving on the bow and stern in three dimensions. (Revell represents all the carvings with decals - albeit excellent ones. I think the old Airfix kit is the only one that shows all the carvings in three dimensions - including the ones that wrap around the stern.) And I think the overall shape of Imai's hull is a bit more accurate (though I'd have to compare the kits with the drawings to be sure).
The big old Revell kit does score on several important points, though. The Imai kit's upper spars - largely because of the smaller scale - are a little heavy; Revell's are closer to the mark. Revell did a better job with the trailboards, making separate pieces for them. (Imai's trailboards are molded integrally with the hull halves. The Revell kit has those wonderful crew figures. And, above all else, the Revell one is just plain bigger - which, in addition to making the finished product more impressive, makes the job of rigging simpler.
The bottom line: both of them are nice kits, perfectly capable of being turned into serious scale models. If, heaven forbid, I were thinking of building a model of the Cutty Sark from a kit, I'd probably pick the Imai/Aoshima version. But that's a personal decision. (I would certainly choose any of the plastic Cutty Sarks - including the Airfix and Minicraft ones) over any of the awful HECEPOB ones.)