I've been hunting deer for 49 years, and have used factory ammo for all of them and just kind of got into handloading last year for my .357 Mag, and my 45-70 so I'm not too anal about the type of ammo I use, and to tell you the truth I use what is on sale most of the time.
I can't remember ever losing a deer that I shot because of the ammo, and not all the deer I've killed were perfectly placed bullets either, but they did get the job done, and I've used all the brands of cheap ammo out there.
Last year I shot a buck and posted here that the bullet was in two pieces as it was a Remington Corelokt out of a .270 at 150 yards angling shot, but the deer went down about 100 yards from where he stood, but the end result was always the same.
Buck fever and poor preperation, such as not sighting in properly, or just taking a shot you shouldn't, has more to do with how the bullet performs than anything else.
Shot placement is more important than the price of the bullet, or the brand, but that's just from my experience!