The alienist has some problems....it's a PrC that gives you a glorified Toughness feat three times, and makes you suffer penalties almost every time.
I guess to a certain extent I wonder what I was expecting from a full-spellcasting class. I ask myself, "what does a sorcerer give up to gain these abilities?" For the alienist, the things they give up are tied to the mechanics of the class (since the class does get full familiar progression...); those Wisdom and skill penalties are the price to pay for a few Toughness feats, a Cloak of Resistance +1, and some Metamagic feats....all and all, not the best kind of exchange, nor does it seem particularly flavorful to me....
But my vote went for the Mindbender simply because I include psionics in my campaigns, so having yet another telepathic buttkicker isn't really something I need.