I have a problem with Sling stream picture quality in Windows 7 on both sling.com and Desktop Sling Player. The edges in the video are rough, not at all smooth. Looks like when antialiasing is off in games. It's mostly visible in the on screen texts. I have had the same problem in Windows Vista but it was solved after switching to Windows Vista Aero desktop theme. Unfortunately I haven't found any solution for Win 7. I have the latest nvidia video drivers installed and I have also tried editing SBcore.ini (video renderer 1-4) but no luck
I switched to Win7 because Win Vista had another problem - when I viewed the video in fullscreen, the HDMI signal started to drop out constantly - weird.