Ill toss my vote in for Vigilance - testing it right now and about to fork over the $40 bones to Jestro. Seems better than thesis that I have been running...and here is why:
Dynamic H1 tags - wow. Very cool. A few of my posts have jumped dozens of places up the google ranks because of this feature.
Cleaner code for Vigilance. Thesis is getting VERY bloated with its newest 1.5 version. It outputs a nasty 20k file for its backend interface that Vigilance doesn't have. Sure 20k isn't much but it can slow things a bit and I would rather have that 20k to place icons or pictures on my site.
* I hope the Vigilance designer keeps the code trim and avoids the temptation to include every custom option known to man. I see people using Thesis themes creating some horrible typography and annoying layouts "just because they can." *
I also like the position of the article tags in Vigilance as wells as its comment bubble location. It cleaverly places beautiful white space around the post title.
Vigilance creates awesome lists from tag links and category links - OH I hope he never removes this feature. I used to hand code this into older themes (thesis does a list as well so in this reguard both themes are similar - Vigilance is cleaner looking and loads faster) and it was annoying as all heck.
Lastly, Vigilance handles complex plugins with much greater ease than Thesis does - by this I mean plugins that produce ajax, javascrip, or plugins that generate image galleries. Thesis is a headache to get working with some of these plugins but Vigilance hasn't had trouble with any I have tossed at it so far.
The only other theme that has impressed me as much as Vigilance is Tarski - very lean and mean - but right now Vigilance is my favorite. Ill update this post with pictures and comparisons if anyone cares when I get back from work.
My .02 cents