A couple posts back I shared a few pictures that I took of a Great Crested Flycatcher using my digiscoping rig, and commented on the results, my technique and my expectations. All in all, my jury is still out on digiscoping, but I am definitely going to be trying it some more. For example, next month Tammy and I are going to spend a week in and around Yellowstone National Park, and I expect that there will be more than a few chances to photograph far away wildlife in a setting that is controlled enough for me to digiscope.
The phrase "controlled enough" is key. I am not skilled enough with the digiscoping rig yet to be able to quickly point to a new, or just moved target, and then get it in focus. I still need a non-trivial amount of time to do that (relative to the time I need when I am simply using my camera with a telephoto lens).
As an example, here are a few more photos of the same Great Crested Flycatcher, but these were not digiscoped. Instead these were taken with my normal camera configuration: hand held Canon EOS 30D + Canon EF 100-400mm 4.5-5.6 L IS. I think the quality of these are better than those I obtained when digiscoping, but more importantly, I would never have even gotten these photos if I had been trying via digiscope. My chosen subject was way too active for me to keep up with it when using the scope.