Personally I find them hard to read without any padding and it is much easier to read tables when they have alternating colors (I think some people like to call them zebra tables).
That is about it though, just a nitpick with my tastes.
For whatever it's worth, I personally really like your site design. You likely don't remember my feedback on my difficulty navigating it, but I actually appreciate its simplicity and lack of overweening bells and whistles.
I'm far more likely to be in your target market (despite not being an actual customer) than your average "web app" guy; so I think you're on the right track.
