If you are seeing choppy signal on your computer with a brand new Slingbox installed, then I would guess that the problem is with the Internet connection between your Slingbox and the computer that you are viewing it on. It could be with the router configuration in the location where the Slingbox is connected, or it could be with the network configuration of the computer on which you are watching the Slingbox streaming. For the latter, I would first consider assuring that your computer's network configuration is optimal, which you can check with free software such as TCP Optimizer, which you can find at http://www.speedguide.net/downloads.php
If you are watching on a computer that is connected via wireless to your home router, then it is also possible that your router is getting a lot of interference, which can happen if you and many of your neighbors have their wireless routers all tuned to the same, or close by, channels. You can check whether that is the case with the free software inSSIDer, which you can find at http://www.metageek.net/products/inssider/ It's best to try to get YOUR router channel to be at least 3 or 4 channels away from any strong router signals from your neighbors.
Also, many routers have options to provide "Quality of Service" for assuring that every device connected to it gets a "fair share" of the bandwidth. These settings can influence multi-media streaming adversely, so you might check your router for any settings related to "WMM" or "Multimedia Streaming" (which are usually "enabled" or "disabled") and try changing them from whatever their current setting is to the opposite, to see if that improves the viewing.
I am a sr. network professional, troubleshooting IP voice networks for enterprise corporations. VOIP is very dependant on reliable and consistant data throughput. I only state this as reference for my background troubleshooting realtime streaming data networks.
My slingbox pro HD also studders, every 10 seconds or so it pauses for 5 seconds. It has never done this in the two years I've owned it, but has recently started doing it. It does not mater what time of day or what location I connect from. My real-time firewall bandwidth usage graph shows the data throughput is constantly 600kbps uploading to the internet.
My client pc can download at 5000kbps consistantly.
It skips with the web player and it skips with the desktop player.
More than that, the desktop player shows the status of the buffer and it skips frequently for seconds at a time while the buffer reports 100% constantly.
Lastly, I run ORB which is a video streaming product similar to slingbox and it streams perfectly fine without interruption indefinately, at the same bitrate.
This evidence is concrete, there is something wrong with the slingbox, probably related to the last firmware update.
The problem is not QOS (by the way, setting QOS on a home router has virtually no effect for internet traffic, and even less if nobody is home uploading)
The problem is not the Internet connection (even the slingbox buffer meter reports perfect network conditions) and other applications work fine.
I've also noticed that manually setting the bit rate and manually setting the image size/quality has no effect. It is ignored.