I use the round nose or flat tipped bullets because they expand more reliably at slower velocities. At longer ranges I would use the 150 grain partition golds I bought for 4.95 a 50 box.
I wouldn't say the slower heavier bullets kill any faster. I would say they they kill as fast as the lighter/faster bullets without the wasted meat.
Penetration has never been an issue. I have killed deer with 30/30, 32 special, 7.5 swiss, 308, and 30-06. Regardless of the load combo in these calibers, on over 40 deer, I have only recovered one bullet. After going through the neck and 5 or 6 vertabae, it stopped, and so did the deer.