That's a highly personal choice to make. Everyone's mileage will vary, etc. However I choose disc based because I just prefer physical media. One thing I barely missed out on the PS3 release was the "Pandemic" limited edition. That would have been a cool Chotchkie to have on display. Can't get those if you go strictly digital, although its a moot point on this PS4 release.
I do hate to wait for something I paid for, so mail order for physical discs (Amazon) is out. Guess I am just "old school" and impatient. I may be lead to change if I get on the playstation TV bandwagon however and if pre-loading becomes a standard.
Also I would not worry about Sony not allowing you to download the game. Proof of concept is that you can still get 50 Cent: Blood on the Sand (?!), Ridge Racer 7, and Burnout Paradise in the PSN store today. So I would imagine Sony would keep their crème de la crème title available for a long time.
Warning: I make a lot of mistakes but occasionally I learn from them!