Not much experience wiht the Hot-Cor bullets, but I can tellyou I have a high regard for the Grand Slam bullets - at least the older dual-core versions. Thecurrent Grand Slams use a single core. It is harder than typical lead cores but soft enough to expand. If they work anything like the older ones they are veery good buullets.
Took me 20 years to recover one of the old Grand Slams. That one was stopped after destroying both shoulder joints of a 5x5 bull elk. It was recovered from just inside the flesh on the off side, didn't make it through the hide.