DSLR's are for photo's Video cams are for Video. Usually what they are designed for they do the best.
As far as ease of use and quality, an DV HD video cam is the way to go, (my opinion).
I have been using a Sony CX500 HD cam for about 3 years now and I must say I get great results.
I tried a couple other cheaper cams that I sold. I'd really like to be able to have two of these.
I am a sound tech with my own company as a side line business. I run the sound for several groups around town and a couple of big festivals. I have been involved in a few projects when the band hired their own videographer. Well the results where not always what they expected, some of the best shots where from my Sony at the back of the room.
Which I almost always run, since I usually have to mix the audio from the music record system and sync it with the video. This helps me out in the video sync part to have a constant running video. Oh another thing, with internal and biggest SD card available. The Sony can run most all day, in HD high res, I do need to drop the video for the day if I have a two day event.
The biggest problem with the DSLR's that I have seen, was lighting, which my cam did quit well with cooping with.
I can't say the video resolutions and focus was any better on some of my shots, but generally with choosing the right scene lighting mode it does quit well. Going from the stage lighting in one scene, a quick button click or two to change the scene to Fireworks to catch the fireworks display. Software I use is Pinnacle Studio..