I have taken a couple of deer with buckshot. I would not recomend buckshot beyond 50 to 60 yards, and I'd prefer #1 buck over 00 or 000, it patterns better, and is just as deadly, IF you stay within buckshot range! Anything beyond 50 to 60 yards with buckshot is a "hail Mary!" Which is fine in football, but not very ethical when hunting fine game animals such as the Whitetail deer!
I will probably never use buckshot again, unless I know for sure I'm going to have very short shots. Buckshot is deadly, but does not expand like bullets do, so if your deer doesn't drop on the spot, you could be in for a hard, if not impossible tracking job! The farther your shot too, the more likely it will be that the deer will not drop on the spot, and the chances for recovering the deer will be slim to none!
Give me a rifle, a slug, or a bow any day, over buckshot!