I've been using a Digiflash for a number of months now (since April 2005), and I love it. I use it mostly for incident with meterless 120 folders and with my 35mm rangefinders, and I've had good success for B&W, color neg, and color transparency films in a number of formats. It tracks well with my Gossen Luna Pro F, within 1/3 to 1/6 stop or so, in both ambient and flash metering modes. See the links below for some observations in shooting under ballasted lights, flourescent and HID lamps that cycle on and off rapidly. There are some oddities that can be worked around if you are aware of them.
I love mine. I always put it in the bag or a pocket, something I rarely did with the Luna Pro F because of bulk. It's also handy for setting an exposure and then comparing for relative adjustments as light changes (see my APUG article for that). It also works very well one-handed, which is great if you're shooting handheld and the other hand is needed for the camera.
You can find the instructions online in .pdf format, which gives all the specifications and lets you see how to work through menus. It's not all that complicated.
My suspicion is that it's PIC based, and programming takes care of linearizing response, which is very well matched to my Luna Pro F across the range of the Digiflash.
See more of my observations and others at:
(there was a url link here which no longer exists)
and:
http://www.photoethnography.com/ClassicCameras/index-frameset.html?lightmeters.html~mainFrame
I think the Dante Stella review is a bit hard on the meter. I really like mine a lot and use it constantly.
A couple of weeks ago someone jostled me at an indoor soccer game and knocked mine three feet onto a concrete floor. No damage at all, and it works fine. Karen Nakamura's put hers through the clothes washing machine and it came out working fine.
Lee