I'm going to begin pay in a campaign and am playing a Psion Telepath, who'll become a Mindthrall. So I'm an evil face -type who enjoys controlling people. I've never played a Psion in Pathfinder before and I'd like to know which of Mental Intrusion and Impose Will would be more useful to me?
I'll be the only Psion in my group and quite possibly in the campaign world (I'm from another dimension), so some powers wont be useful to me at all and I won't be going up against other psychics.
which of Mental Intrusion and Impose Will would be more useful to me?
What you need to do is plan ahead and take a look at the powers you plan to pick up. If many/any of them do NOT have the typical boilerplate augment where +2 pp = +1 to the DC, then Mental Intrusion is good. (It's basically a feat, only specific to charms/compulsions.) If the powers you plan to have DO mostly/all have that boilerplate, the ability won't do you much.
Meanwhile, know that Impose Will increasing your manifester level won't do much either overall. Mostly for charms/compulsions it's going to increase the duration. That and help you a bit against Spell/Power Resistance. Otherwise it's not that big a deal. Yeah, you might get access to augments that allow different target types etc a bit early, but meh. Again, take a look at the powers you plan to take.
Ok, Anguish. Thanks for the advice.