WebSlingPlayer renders much smoother pictures than the regular SlingPlayer. The difference is particularly apparent for sharp features as shown below (click on the image to see the pixel-by-pixel image).
I tried copying some files from the WebSlingPlayer program directory to the SlingPlayer directory to see if it is possible to have the WebSlingPlayer picture quality in the regular SlingPlayer since I do not like the WebSlingPlayer. It turned out that copying SBDS.ax and H264DecoderDLL.ax works. Here are the versions of the players I tried:
WebSlingPlayer (IE8): 22.214.171.124
OS: Windows 7 Professional
I tried the same with my netbook running Windows XP, but the method above didn't work for some reasons.