Digital has been preference from launch, though on occasion I do still go for a disc copy. If it's a big budget title like Call of Duty, and I just want to blast through the campaign and be done with it for another year, then I go disc.
General rule of thumb regardless of the game - if I am likely to purchase a season pass then I see that as money I can't get back, so figure what the hell and go all-in on digital. Same applies to lengthy games, typically open-world stuff or something that I am likely to spend a large amount of time in multiplayer on.
I mainly like how quick it is to launch into a digital game, whether accepting a game invite, by voice, or pins, it's super quick.
Funnily enough even on 360 I found I would mostly jump in and out of various digital XBLA titles just for the same quick easy access, and typically leave my favourite disc game in the drive. Now, on XB1 I tend to just launch into whatever I am in the mood for.
However if these large games could magically play off the disc like the majority of 360 games, then I no doubt would have stuck with discs for most titles. As it is currently, I just see it as all digital regardless of download or disc - download gives your account the license or a disc copy needs to be inserted for license verification. Either way it's a chunk of HDD space gone and I find the former far more convenient.