Basically, if you want the reports to look good on the display, you need to specify the line widths in pixels using integers. If you calculate based on 96dpi, one point is 1.33 pixels. Since there is no uniform way to display 1.33 pixels on the display, each application decides on its own how to represent the line. This is the most common cause of borders appearing thinner or thicker depending on the zoom and scroll of the document.
Our recommendation is to set the border to 1px or 2px, for example.
Have you tried the new visualization options in Telerik Reporting Q2 2013? You can get them from your account.