It's true that ultimattes have wider range & more adjustments than switcher chroma keyers - but that's only important if you have a trained ultimatte operator monitoring & making adjustments. From what I've seen, most places have somebody come in and set up the system & then expect the Video Op or TD or even Maintenance to keep things adjusted on a daily basis. Because of changes in lighting, wardrobe, and camera shading - not to mention a lack of ultimatte operating experience on the part of the station personnel, these systems if not adjusted don't always look as pristine as they could. From a TD perspective, you would just take cameras like you normally would & these cameras are composited images. Some places tie up a full M/E for the background input to each camera...others use AUXes or even dedicated CGI sources. And some places have the CGI systems do the switching, so that you only need one CGI processor - this also induces a delay between the raw camera & the composited feed so that the CGI system can track the camera positioning & adjust the CGI image...similar to how there's a bit of delay in the camera feeds for those inserted imaginary 1st down line markers on sporting events. This type of system when used in a news enviornment can effectively get rid of the switcher from the equation. But a distinct advantage of the higher-end ultimatte-based CGI systems over standard chroma keyers is that you can perform camera moves and the background will track properly. If you stick with the already-installed switcher-based chroma keyers, you can still get a good-looking key, and the adjustments are such that most TD's need no additional training to maintain a clean key signal. You will, however, be switching cameras by cutting on the keyers. You can set up the switcher to automatically update the chroma key settings on each keyer when the TD switches using Key Memory; or you can use M/E Snapshots. Personally I prefer to use the 8000's Key Snapshots - each keyer can switch between 4 pre-learned settings, so one keyer could handle 4 different chroma key cameras. Unless you installed some extra equipment, you would however lose the ability for the virtual set to track any camera moves. Unless all that you're going to do is to take locked-off camera shots (which means that your existing chroma keyer would be as good of a solution as any), most virtual set places will want to sell you their system that lets the background track the foreground - I've even seen a system at NAB that uses fixed cameras but uses interpolated images between the cameras to make locked-off cameras look like they're trucking & dollying with the background.

If you do it through the switcher, you're burning an M/E (or a portion of an M/E) to key a person over the virtual set. If you have an ultimatte, the person is key'd over the virtual set all in the ultimatte and that composite comes to you as one source. The ultimatte would save you switcher real estate but would obviously cost more money. On the flip side, if you guys go with ultimattes, that brings up other issues.

I believe, or so I've been told, that the Ulitmatte is a better keyer. You have many more adjustments then you do with the Sony keyer.