Been here long enough, you know I'm a die hard Marvel fan... (and pretty much hate DC). I've been happy recently what with Bendis writing my beloved X-Men... but I haven't been thrilled with the product for a few years mainly due to event saturation.
I always preferred Marvel because their heroes were more real, and they were allowed to evolve and change. A few years ago, Marvel decided every year would have an event-- like TV seasons. It's a fun idea-- but with no break, event saturation started to effect continuity everywhere and it's hard to just follow the characters you like with all the tie ins.
Lately, there has been time travel and multiverse jumping galore in every book, and they've been saying the space time continuum isn't doing well as a result.
This leads to the next big event-- Secret War and it would seem... even though they deny it.. they are pulling a DC, which makes me really unhappy.
I HATE alternate reality stories, I always have. I despise DCs New 52 and the fact everything seems to revolve around alternate worlds when I thought the point of it was to simplify their eons of different eras and continuities.
Marvel has a multiverse as well, and certain books have always played it up-- but as far as pure continuity, they've been running two primary universes. The core Marvel universe, and the Ultimate universe which was started around the turn of the century to reimagine everything as if everything started then instead of the 60s.
In Secret War, it seems that the two Marvel universes are being merged/fighting each other. They are being coy as to what the end result will be, but based on EICs talking about this being a chance to resurrect, retcon and reestablish certain things, it would seem as if one of a two possibilities is likely:
One, they are pulling a DC and rebooting everything by merging the universes and creating a two new ones. Why do they need to do this? I don't know-- their continuity is fine. Most fan guesses surmise Marvel is out to re-establish their prime continuity sans the properties that they do not own the film rights to in order to make brand synergy more intact. They've already subtly retconned most of the Avengers to match their movie counterparts where needed.
This would basically spin the Fantastic Four and X-Men into their own universe. FF has already been cancelled. The X-Men are too popular to cancel and the x-books are an easy 3rd of Marvel's total print product... but with them set into a new continuity they could pretty much do whatever they like with them... and the plan currently seems to be to make the product as far from the X-Movies as possible. Also, and this would likely be the most controversial aspect, joining the FF and X-Men in this new continuity would be Peter Parker, Spider-Man. Why? Because Sony owns him and the Spider-Man of the Ultimate universe is Miles Morales... who Sony does not have the rights to. There's no way Marvel would shuffle off their mascot to an alternate continuity... but if Miles changed up his costume to the classic Spidey-digs, problem solved. Spider man, in prime continuity, just not Peter Parker.
The second possibility is that they are just winding us all up to sell comics and none of this is going to happen... but solicitations of books after the event are slim, with most al the Ultimate books being cancelled. But this isn;t without precedent. In the 90s, the Age of Apocalypse event saw the faux cancellation of every Marvel book replacing them with alternate universe titles. So they could be playing us...
But it's hard to deny that with FF being cancelled, Wolverine being killed, and Miles Morales being the star of the Spider-verse event over Peter Parker that Marvel hasn't made it a priority to stop helping market share of competing studios.