User blog comment:Colin HEX/Which Skill is Better?/@comment-3224196-20150711092635/@comment-26971153-20150713042942

BAE expert 25 gives you 99% resistance if you have a base of around 8000 points. Tough Body 25 gives 54% damage reduction, even to dark minions.

Both are useful. I'd suggest enough BAE for full resistance if you're going for a near-invincibility Heavy, and full Tough Body.