The first albums I ever owned were Pearl Jam's Ten and Nirvana's Nevermind. Until the "first albums" poll of a couple of weeks ago, I hadn't revisited either of them in years - since college, if not longer. I think they hold up pretty well.
In 1991, I was slightly more into Nirvana than I was into Pearl Jam. Revisiting the albums seventeen years later (has it really been that long?), that order is now reversed. Part of it, I think, is that Nirvana's album was more of a game-changer at the time, at the transformative effect of Nevermind has been diminished as alternative rock has continued to reinvent itself over the past two decades. Ten was, in some ways, more modest in scope, but, to my ears at least, sounds a little bit less dated, perhaps because Pearl Jam, unlike Nirvana, has continued to make new music, and therefore its early stuff still sounds like the work of a contemporary band. Then again, "Smells Like Teen Spirit" has been viewed 25 million times on YouTube, and "Even Flow" has not.
A commonly drawn analogy is that Kurt Cobain was to Generation X what John Lennon was to the Baby Boom generation. I think that analogy overstates Kobain's importance - he was enormously talented, but he produced only a fraction of the body of work that Lennon produced, and he didn't change the path of popular music in several different directions, as Lennon did. Kobain is probably best compared to somebody like Jimi Hendrix - enormously talented, but somebody who died before he reached his full potential. Kobain changed the course of rock music, but he wasn't the political or cultural force that Lennon was, and I tend to associate him with Seattle more than anybody associates Lennon with Liverpool.
Eddie Vedder was more edgy and political, and more personally reclusive - in some ways, a better analogy to Lennon, though obviously without the same popular stature. My guess is that Lennon and Vedder would have had a lot more to talk about than Lennon and Kobain, but that's just a guess.
Here's some music:
Pearl Jam - "Black"
Pearl Jam - "Alive"
Pearl Jam - "Even Flow"
Nirvana - "Smells Like Teen Spirit"
Nirvana - "Lithium"
Nirvana - "In Bloom"