Glad to have you all here. Coming from the world of Wilber (it's Wilber with an 'er' btw; Wilbur always makes me think of the pig from Charlotte's Web), I was getting a little worried.
You're diving into the deep end, @kevboh. Some find Wilber hard, but he has also simplified and popularized himself in many different books and other media, so there are beginner's access points. And, he's an American and speaks in ways that are generally more familiar.
Gebser I'm finding particularly challenging, now that I'm digging in, partly because his knowledge of art and cultural history is so acute and his larger points are so intimately grounded in these historical examples. I think you have to engage with the details more, whereas as Wilber emphasizes what he calls "orienting generalizations" and the details don't tend to matter as much to him; in fact they're practically dispensable or interchangeable.
In any event, I hope you stick with it. I think David Foster Wallace would have appreciated Gebser. I could imagine allusions to him in James O. Incandenza's fictional films.
As a random sidenote, I notice while I'm reading these first pages that my mind is also drifting to Jorge Luis Borges, who wrote with a similar sense of erudition (i.e., all the references to obscure writers and historical studies), albeit of course much more fantastically and playfully than the serious work Gebser is proposing.