I've hunted with ballistic tips for the last 20 years, with very good results.
I've killed at least 2 dozen deer with 165gr .308 cal BTs out of 3 different 308win rifles (muzzle velocities ranged from 2675-2800 across those 3) from ranges of 75 out to 360yds, all were complete pass through so no bullets to recover, but based on shrapnel left behind (even in the one I shot at 360yds), they definitely expand, lets call it "aggressively", and dump a ton of energy into the target.
This year I finally broke down and jumped on the 6.5 Creedmoor bandwagon, and loaded the 120gr Ballistic tips over Varget and H4350. Both are very mild loads pushing 2800-2825 fps and both with single digits SDs and sub .5MOA accuracy. That's about 150-200fps slower than what the book suggests for max loads but Im happy with the accuracy, consistency, and the fact that it perfectly matches the trajectory/performance of my heavier 308 loads (165gr NBT over varget in a 26" Remington VLS @2800fps, the 6.5mm 120gr has nearl identical BC and Sectional density to the 165gr 30cal). I settled on the H4350 load as it had lower ES than the Varget load and took it hunting this year.
I have shot three deer with this load:
First was a medium sized whitetail doe at 373 yards, full broadside double lung shot, dropped dead in her tracks (bang... flop), bullet hit a rib while exiting but was otherwise a clean passthrough w/ no bullet recovered but inside was red soup. so similar performance to the ones I have shot with the 308.
Second deer was a 4.5yr old cull buck, probably weighed 150lbs or so before field dressing. range was ~150-160yds quartering towards me, bullet entered ahead of front shoulder, broke three ribs on the near side, blew out one lung and nicked the back 1/4 of the far side lung, found the bullet just under the hide right behind the rib cage. Bullet expanded to about 2x caliber and core completely separated and found bits and pieces all along the wound track. Deer took one step backwards at the shot and fell down dead.
Third deer was another medium sized doe, unfortunately we werent able to recover her, shot was broadside around 100-125yds, both the shooter and I heard a solid thump of the impact and down range we found chunks of bone, hair, and a very good blood trail leading away from the place she was shot. For whatever reason though she had enough gass left to make it to a fence line and into a densely wooded property next to ours almost 200yds from where she was hit. The blood trail petered out leeding up to the fence and we couldnt get in touch with the neighbors so we werent able to recover her. The shot was downhill and my only guess was that it was maybe low, but the damage evidenced by the blood and bones we found around the impact suggest that it wasn't due to bullet failure that we lost this one.
Overall very impressed from my experiences with ballistic tips.