I've seen video clips, so I sort of knew what to expect, plus she has had several years of touring with David Byrne and her own band to refine the presentation of music that is quite eccentric. A bonus for this night was that Hopscotch brought in the amazing See Factor company for lights and sound - top level staff and gear, VERY nice. It helped, too.
I was honestly amazed by the quality of the performance we saw. Her music is not easy to pull off live, even IF much of it is knitted together in Ableton Live, the sheer number of transitions and changes is a real bitch to execute. Lots of stuff I assumed were synthesizer riffs or fills are actually Annie's Albert Lee model guitar, heavily mutated. She sings wicked complex melodys over spazzed out rhythms and plays precise 16th note runs while doing it.

She's not your normal shredder, but fuck me, AC can play. In the middle of a noise-scape that would make Vernon Reid twitchy came a few clear, singing guitar notes with Larry Carlton vibrato. She hybrid picks savagely. She is fast, accurate, and marvelously weird. Her voice is fantastic live. I don't know how she does that on a regular basis. It's HARD material to sing.
A few times I was reminded of the Moody Blues or Brian Eno. The electronica angle is super, I love synths that are naked and sizzly and there is LOTS of that.

I think and hope that St. Vincent is just getting up to cruising speed and has a long way to go yet. Annie Clark works her skinny ass off for your concert dollar, and if you are a fan AT ALL, I recommend seeing them if you can. Money well spent !