I'm a huge fan of The Village of Hommlet. I consider it one of the most perfect low-level adventures ever written for any edition of D&D and have probably played it more times than I can recall. The original module was released in 1979, with a monochrome cover. That was the version my friend's older brother had, but the one I first owned was the 1981 one with Jeff Dee cover art. What's interesting is that, in the two years between the initial release and the change in the cover art, module T1's sequel, The Temple of Elemental Evil, was never released. This baffled and disappointed me, as I was used to TSR's comparatively rapid release schedule of other modules in a series and I was looking forward to seeing what greater evil threatened the good folk of Hommlet.
In the years since, I've learned some of why it took six years for The Temple of Elemental Evil to be published, but, at the time, I couldn't imagine why it had taken so long. In the interim, I'd put together my own Temple and had some fun with it, but I assumed my own efforts would be a pale reflection of the "true" one -- once Gary Gygax got around to writing it. As it turned out, the published version of the Temple wasn't written by Gary Gygax, or rather it wasn't written solely by him. As I understand it, Gary created an outline for the module, which Frank Mentzer fleshed out and expanded upon. The result is a module that feels very inconsistent to me, with shifts in tone and content throughout. That's to be expected, of course, given its origins, but I think it detracts greatly from what should have been a terrific companion piece to The Village of Hommlet.
No published version of The Temple of Elemental Evil would have lived up to my expectations after so many years of waiting for it. Likewise, D&D itself -- and my relationship with it -- had changed considerably in the span of time it took for module T1-4 to appear. Whereas The Village of Hommlet was the product of an earlier, more "sandbox-y" age, the first of TSR's "super modules" was a product of a time when modules couldn't just present adventuring locales; they had to present stories as well. Now, The Temple of Elemental Evil is not Ravenloft or even Pharaoh, but neither is it Vault of the Drow. T1-4 is much more detailed and background-heavy an adventure than those of the Golden Age, filled with all sorts additions that both unnecessarily complicated its presentation and seemed at odds with what was implied in The Village of Hommlet. In short, it wasn't what I was expecting at all.
None of this should be taken as a condemnation of the module, which I think holds up better than it ought to, given its various infelicities. Frank Mentzer made a very valiant effort at trying to be true to what came before while also taking into account changing sensibilities about what a D&D module should be. Goodness knows I used the Temple to good effect in my old campaign, although I changed many of its elements, eliminating things I felt weakened its premise and adding elements I expected to be there -- such as Lolth -- based on what we'd been told in module T1. T1-4 is, I think, a diamond in the rough, but there's a lot of carbon that needs to be shorn away before it can truly shine.
On the current debate regarding its megadungeon status, I side with Joseph Bloch and say that, for both historical and stylistic reasons, The Temple of Elemental Evil does not qualify as a true megadungeon. Of course, I don't believe it was ever intended to be perceived as such, so this is no mark against it and I think viewing it according to this category only makes it look like more of a failure than it is. As I said, I think T1-4 is solid and workmanlike, but it's not a classic on par with most of the Gygaxian canon or even lesser TSR works from 1978-1981 period. It's an attempt to capture something of the feel of the older style of adventure module and conform it to the decadent dress of late 1e, a project that, in retrospect, holds no appeal for me, but I can certainly understand why those for whom the Hickman era or post-Unearthed Arcana AD&D were their introductions to the hobby would find it far more attractive than I do.