I think it is a great show. I have only seen two productions, the original and the revival with Antonio Banderas. Very different and I thought both were great. To me, the score and direction (both productions, but especially the original) may together be close to the finest..., but I have always thought the book was a little choppy, which I admit may have been due to the episodic nature of the basic story. I also think it took too long to care at all about Guido, which was probably the intention.
Ironically, I would've said that Gypsy was the finest ever written, but lately I have found myself getting bored periodically during the show (off the top of my head, I have seen productions of Dolly, Les Mis, Follies, Evita, The Producers, Mame, Company, and A Little Night Music more than Gypsy, but I have never been bored in any of those). So, I would have to think long and hard re the finest ever written.
The movie to me was even worse than anyone here has said so far. That big production number that Kate Hudson did was, to me, maybe the single worst number in musical film history. I cannot think of a movie musical based on a Broadway production that came close to being as bad as this one...wait, I can. The movie version of The Producers was just as bad as this,which is amazing when you consider the fact that it practically duplicated the show...which of course was the problem...it was not cinematic. (The other oneI could mention is Mame, but that is for me a guilty pleasure, i.e., I know it is bad and that Lucy is atrocious, but I find enough to enjoy in it that it is not in the same league as Nine and The Producers. c