The first few levels will come lightning fast, but the bulk of them up to 60 will be comprised of between two and three hours of gameplay. After that, it will get a bit slower, thanks to some input from beta testers. By our math, that leaves five hours per level including and after 60, but who knows how that will be distributed.
Whether this ends up being faster than competing games like World of Warcraft and The Lord of the Rings Online by the end probably depends on your play-style. He said "on average," so does that mean the hardcore achievers will reach the top in 90 hours and the casuals will mosey on up there within 500 hours? There's been a lot of chit chat and speculation in the Massively office about this news. We suppose we'll get a good sense of it by midway through the summer.