I've gone full digital, and I have few regrets. I miss having an actual book in my hands, but space is a more important commodity than the benefit of having a physical book.
There is one perturbing feature of Comixology, though, that could so easily be fixed but won't. Comixology will not save downloaded books to your SD card (though obviously if you're an Apple user, this doesn't apply). I always like to have a few extra gigs of storage available on my phones HDD, but if I am going on a long flight and want to have a collection of books available to read, I can't just rely on all the storage space on my SD card. What a bother. I mean, I get why it's that way, but it's still a bit irritating that you have to shuffle around files or delete and re-download books.