The Slingbox SOLO has component cables, so you can connect connect a HD cable box, satellite receiver or a DVR. You will not be able to stream HD (only the Slingbox PRO-HD) but the picture quality is very good. With the original Slingbox the best quality that you will get is using the S-video. So the answer to your you question is yes, you will get better quality using the Slingbox SOLO.
Remember, if you own an original Slingbox and you will get a new Slingbox SOLO or a PRO-HD you can use the upgrade program