A quick test now comparing the results with that of my UV enhanced High Power Xenon flash when doing reflected UV photography.
Equipment used was: Nikon D70 (unmodified), Baader U-filter, X35 lens. Exposure: f8 and 2sec for the UV flashlight, 1/160sec for the UV flash at ISO400.
[click on image to get a larger one]
I guess the UV flash investment is well worth it, since it reveals much more fine details, stimulates all RGB channels of the camera chip and seems to also go much deeper into UV (a prior result showed response down to 320nm). But I have to be fair, for a simple setup or a beginner on a tight budget it might well be worth trying and move on later.
Stay tuned, more will follow on that fascinating subject...
More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos