I made the switch about 1985 for deer and elk, never looked back. I still have a nice .270 stored away, I don't think I've shot it since then. If I were to use it today, it just wouldn't feel right, like I'm trying to blow the animal up, rather than harvest it with just the right amount of power and skill.
If I found myself hunting in the high power season, I definitely would still use a traditional muzzleloader. Bill