Video quality is limited by the upstream connection available from your Slingbox.  If your upstream bandwidth available is less than 1 Mbps, this will result in lower quality video.  Bandwidth that is 1Mbps or higher will result in higher quality video, more similar to what you would experience if you not watching the programming via your Slingbox.
  
Additionally, when first connecting to a Slingbox from SlingCatcher, it will take 1-2 minutes for the stream to optimize.  During this time, you may see audio/ video sync is off.  These issues should resolve once the optimization is finished.