One of the big reasons I prefer the Marvel over the DC universes is the way that with the exception of the Ultimate stuff, it’s largely all taking place in the same universe at the same time. The narratives intertwine and contradict and are usually brought together for whatever the big crisis (i.e. marketing crossover of the given year) occurs.
It’s big and messy and I can see why some people hate it, but there’s something about intertwining narratives that really appeals to me. I love the idea that whilst in one street Spider-Man is fighting Sandman or Vulture, in the next Daredevil is hunting a criminal, that there are lots of stories carrying on at the same time.
Of course, you then get those odd panels where Spider-Man talks to Daredevil and there’s a little asterisk, telling you in the box out to read more about the other character in their own title.
Trying to read all these comics normally would be expensive and not very satisfying. With so many writers and so many stories, there are always going to be those you love and those you hate. It’s not really been possible for me to really investigate the nooks and crannies of the Marvel Universe.

However, in recent years, I’ve had a Marvel Digital Comics Subscription, and unlike something like Comixology where you ‘buy’ comics, this gets you access to the Marvel digital library of over 10,000 comics. You have to read on your PC (it requires Flash so impossible to read on an iPad) whilst online and your access ends once your subscription expires, so there are downsides. I also don’t think you get anything more recently published than a year ago. But for me, it’s a great way to explore the Marvel Universe.
I started a project last year to read widely within the universe and starting with 2005’s Civil War I’m reading my way forwards using an extended reading list of the chronology including all the minor tie-ins. The idea is that as comics drop into my list, so I will read them going forwards until I am reading everything through the major event milestones of Planet Hulk, World War Hulk, Dark Reign, Secret Invasion, etc.
It’s a big project and I’m still in the middle of Civil War, ticking off issues in the extended chronology I have (I think it’s well over 100 comics). I’m in no rush, and even though I read Civil War at the time, I’m really enjoying seeing how these different titles link into each other, and even how they contradict each other.