I had used Foxit on my old laptop due to its much better loading times and don't remember any real problem with the text. However, with my new laptop and Vista, I never bothered to add Foxit or others since the load time has been minimal. I do see, though, I'm using Adobe 7 Reader. Now that I think about it, when I went to update to Adobe 8, it wasn't available for Vista. Haven't checked back in the approx. 2 months I've been using the new computer.
btw, very pleased with Vista. Thankfully I have Office 2007.