Just got back my reviews from the Valentine's day massacre. I have to say that I'm stunned, and not for the reason you think.
I've been writing papers and getting reviews for a LONG time now, and I have to say that these are the best reviews I've ever seen, and are way beyond the standard for the typical theory conference. Both papers were rejected, and so the reviews necessarily were negative, but in an extremely constructive way. They critiqued without being critical, were detailed and thorough, and clearly got to the heart of what the paper was about. The comments pointed out what was good in the paper, and more importantly, pointed out what the reviewers felt was missing, and how best to address the problems. I actually felt better about the rejection after reading the reviews, because they came across as genuinely liking the work.
Now it wasn't all good. There was a basic premise at the heart of the rejection that I disagree with, but it's a reasonable point to disagree on, and I can at least see a way to resolving that problem.
At least one other author agrees with me on this assessment - you're welcome to share your experiences in the comments. Congratulations to the PC - theory conference reviews are often slammed, and rightly so, but these reviews stand out for their high quality.