I would have to agree with the majority that mega-adventures tend to run too long and therefore my players and I tend to use shorter published adventures if we have the opportunity. I am currently DMing a homebrew campaign in which i have used several different modules in this order( with various wilderness encounters and political roleplaying in between.)
1. The Wizards Amulet: made a great (and free) adventure to get PCs introduced to each other, and it tied in wonderfully with:
2. The Crucible of Freya: During this module the PCs made friends with several important people in the region, and then from that they springboarded into:
3. The Tomb of Abysthor: the PCs followed some legends and stories about the nearly forgotten Burial Halls and decided to enter both to search for treasure and to try to restore some of the older Deities' glory. After clearing out a couple of levels the PCs got news of some important events taking place nearby (a siege of the Dwarven homeland of 2 of the PCs) that caused them to decide to temporarily abandon their explorations. Which led to:
4. Natural Selection(DUNGEON magazine #85): The PCs got embroiled in a dispute between a Druids Circle and a local Duke. Following their success with this, the PCs were able to secure aid to go investigate first hand the rumoured siege of the Dwarven stronghold of Smaragholt, which led them to:
5. The Silver Summoning: which we just this Sunday concluded. The PCs are fast becoming friends with influential people and of course, making powerful enemies, which opens up plenty of options for both me and them in the future.
6. Without knowing with 100% certainty what they will do next, I would guess that some will call for returning to the Tomb of Abysthor, while some others may call for following the defeated army from the Silver Summoning into the mountains to find their base of operations.
During this time I tried to be careful not to railroad the PCs into their choices along the way, and naturally, there was some internal dissension about the actions and direction of the party, so there were a couple of defectors in the ranks (which really spices things up!)
So far, I have only used about 40% percent of the material I had thought to use, as they havent really surprised me yet with any of their decisions. I credit this mainly to good communication on THEIR part about their own character backgrounds and motivations. Of course, that can change with SOME characters. But I really dont see that a typical mega adventure would have provided all the flexibility that this series of pretty much unrelated shorter adventures provided. And if you throw in the fact that the vast majority of mega adventures are dungeons or variations thereof, they really dont give me what I want IMC. Of course, that can change based on the PCs. But considering our group went about a year going through the Return to the Temple of Elemental Evil before starting my campaign, I think we have had our fill of super mega dungeon crawls for awhile ( i hope).