I just had the focusing screen on my 7D replaced with a KatzEye split-prism/microprism focusing screen, more like an older SLR would have. So far I like it quite a bit.
In addition to the split-prism bullseye, the KatzEye screen offers higher contrast, more visual "snap" when acheiving focus, and much better indication of depth of field. The camera's AF points continue to function normally.
The 7D's focusing screen is not user servicable due to the adjacent transmissive LCD screen, so I had KatzEye install, align and calibrate the new screen. They also cleaned the mirror and the focusing screen area. My split-prism and the AF confirmation appear to be in perfect agreement. Plus, I love that I don't have to rely on Live View to nail my focal plane when shooting wide open. The viewfinder is very accurate.
I opted for the OptiBrite treatment to the matte portion of the screen. This helps to keep the screen bright when using a very slow lens or stopping down significantly. I was pleased to find that although darker than the factory screen when stopped down to f/16 it wasn't by a lot. It was quite usable in an unlit interior on a cloudy day. With the lens opened up it quickly becomes bright and contrasty.
One of the reasons for choosing a high contrast focusing screen is that I have an FL 55mm f/1.2 with an Ed Mika adapter. So shooting manually with a shallow depth of field, the new screen helps get the focus right, especially with moving subjects. It is also influencing me to choose manual focus when using my EF lenses.
The side effect is feeling more connected to the camera than I have in years. I forgot how fun it is, like with an old SLR, to handle the controls and see via the viewfinder rather than trigger servos and scan for blipping AF points. I think anyone could benefit from the upgrade.