I had a deep lamellar graft 15 years ago, for keratoconus, and it wasn't painful, just uncomfortable for a while. The followup appointments also involved some discomfort, but were fine.

As with any transplant, I'd say it might be helpful to prepare yourself for the fact you'll have someone else's body part (I'll be celebrating my cornea's centenary before that long).

And don't have huge expectations for the result -- I can't comfortably read a book with my operated eye, though no doubt the vision would be acceptable with contacts. They're such a pain and the vision in my unoperated eye is still good enough that it's better to rely mostly on that eye than bother with them.

I still won't drive in the dark, won't play contact sports and my eyes get tired fairly easily, but overall it was a big win and I'd go for it again in a heartbeat. Good luck!