There's a few that are great, but overall I haven't been as impressed with what they offer as I hoped. However I don't think I got them all. I think acrobat is one of the most useful (something like you aren't slowed when weapons are out or something.)
Yeah I got that one, one that increases mana bar (awesome), weepers doing less damage, rats only attack when I'm closer, some white rat one that's meh and then a few other crappy ones
Getting up to 6 charms is very cheap from the mechanic guy though, like less than 1k. I don't know what else to spend money on, I've bought the boots from him, the rune, the charm upgrade and the zoom (which I don't use much)
Also I'm basically swimming in runes, I've just finished the 5th or 6th mission and I have Agility 2, Blink 2, Possession 2, Dark Vision 2, and Bend Time 1. I have like 4 runes that I could spend but I'll probably just save them for Bend Time 2. I think I would have liked less runes so I would have to make hard choices, some of the powers seem much more useless than others (like windblast and the adrenaline meelee) so if people just explore a little bit, they will have pretty much everything they could want. I missed like 4-5 runes too