Well, when it comes to Cutty Sark kits I always feel obliged to start by repeating one big suggestion, which usually gets ignored. This is not a good subject for breaking into the hobby of sailing ship modeling. A reasonably detailed, reasonably well-executed model of a three-masted, full-rigged ship takes months, if not years, of work. This hobby is full of fairly short, but steep, "learning curves." A newcomer invariably finds that his/her work improves extremely rapidly; what looks good today will look unacceptable three months down the road. It makes far more sense to pick, as a first effort, a smaller, one- or two-masted ship on a relatively large scale - a model, that is, that can be completed to a reasonable standard in a few weeks. That modest investment in time and money will pay huge dividends when the modeler goes on to a bigger, more time-consuming project - and it will pay an immediate, short-term bonus in the form of a nice-looking model to put on the mantle.
At the moment, unfortunately, the plastic kit manufacturers are making it difficult to follow that advice. The sailing ship sector of the plastic kit industry is just about the smallest, and it's smaller now than it was twenty years ago. A fair number of good newcomer subjects used to be available, but the vast majority of them have been discontinued. I can think of about four that (I think) can be found fairly easily. Three are old Pyro kits from the early fifties, now being sold under the Lindberg label. They're old, basic kits, and Lindberg has put some silly labels on them (for some reason) that can cause some confusion, but they're basically sound bases for serious scale models: the beautiful fishing schooner Gertrude L. Thebaud (marketed under the silly label "America's Cup Defender"), the U.S. Revenue Cutter Roger B. Taney (labeled "Independence War Schooner"), and the U.S. Revenue Cutter Harriet Lane (labeled "Civil War Blockade Runner"). Any of those kits would be a good starter project. Another, more recent kit that would, I think, be good for that purpose is the medieval "Hansa Cog," from the Russian manufacturer Zvezda. I haven't seen that one in the flesh myself, but it's gotten reasonably good reviews and certainly meets all the requirements for a good starter kit. It has one mast, and most of the basic features of a square-rigged ship (without the repetition that can be so discouraging in a larger vessel), and offers all sorts of opportunities for developing painting and weathering techniques. The potential is there for a beautiful, colorful model with a minimal investment of time.
Now, with all that out of the way, back to the Cutty Sark. That ship has actually been pretty well served by the plastic kit industry. The big, 1/96-scale Revell kit has been around for a mighty long time - since 1959, to be exact. Its hull contains some fairly small outline errors, and some of its detail parts certainly aren't up to twenty-first-century standards. It suffers from many of the inherent limitations that can be found in almost all plastic sailing ship kits. (If I were building one - heaven forbid - I'd start by throwing out the plastic "deadeye units," offering up the plastic "sails" and plastic-coated-thread "shrouds and ratlines" in a flaming sacrifice to the styrene gods, and replacing the plastic eyebolts and belaying pins with brass aftermarket ones.) I've also read complaints in recent years that the quality control in big Revell sailing ship kits - especially those sold by Revell Germany - leaves a lot to be desired in terms of flash, warped parts, and low-quality, rubbery plastic. But lots of extremely attractive models have been built from that kit over the past fifty-plus years. It's a real classic; I'm glad to see that Revell-Monogram has reissued it recently. (Maybe - maybe - this new American packaging, which as I understand it originates in China, will show better quality control.)
Revell sells two other Cutty Sarks. The one on 1/220 scale (or thereabouts) isn't bad; I haven't bought it, but on the basis of photos it appears to be basically sound, though pretty small for serious detail work and rigging. The Revell Germany 1/350 kit originated with Imai, and appears to be typical of that company's products: extremely well designed, neatly molded, and quite accurate and well-detailed considering the constraints of the tiny scale.
The old Airfix Cutty Sark is also a nice kit - again bearing in mind how small it is. Airfix has had some big financial troubles lately; I suspect the kit is hard to find (though I think I read recently here in the Forum that it's recently been reissued in a Zvezda box).
My own personal favorite Cutty Sark kit, though, is the 1/125 one that was produced back in the late 1970s by Imai. Imai was a Japanese company noted for its extremely high-quality moldings and ingenious design features. The firm made some of the best plastic sailing ship kits ever, demonstrating what a huge potential styrene has for producing such subjects. Unfortunately Imai went bankrupt sometime in the 1980s, and the kits disappeared. Some of them, however, have turned up again under the labels of other companies. The 1/125 Cutty Sark is now being sold by another Japanese company, Aoshima. The price is high, but it's a beautifully detailed, fundamentally accurate kit - superior in many respects to the Revell one. If you do a Forum search on the term "Imai Cutty Sark" you'll find quite a few posts, written by other people as well as me, singing its praises (and acknowledging a couple of amusing mistakes in it, which seem to have originated with the language barrier). If, heaven forbid, I were in the market for a Cutty Sark kit, the Imai/Aoshima one is in the one I'd buy. It is, in my personal opinion, the best rendition of that ship in kit form - plastic, wood, or otherwise.
Hope that helps a little. Good luck.