Thanks for the info.
I had a chance to try a couple magnifying glass lights today. Both were about the same: 5" diameter glass, 3 diopter, T9 22W 6400k fluorescent light, on articulating arm. One unit had a 90 degree flip up cover; as fivefish said, no need for that. Mostly it felt like it was in the way.
Both units were about $59. For this price it starts to make it hard to justify a microscope - but that's maybe because I haven't experienced a good microscope.
The fluorescent light gave nice lighting - bright enough and the color temp was ok. The light felt just slightly warm when you put your face/eyes near the magnifier; not a big deal but perceptible. If an LED light was equivalent in output and quality it might be better in terms of reduced heat.
The magnifier did a pretty good job and seemed to provide a reasonably expansive view while allowing about an 8" working distance. The working distance could be made somewhat further or closer depending on your eyes and preferences. The articulating arm was ok, not great; it held it's position pretty well but only swiveled about 45 degrees on the clamp mount. One very good attribute (as noted by other EEVers) was that the magnifier/light head provides a bit of a barrier against the updraft solder fumes.
Other than a so-so quality articulating arm the only thing that wasn't quite ideal was the 3 diopter magnification. I think a bit more magnification would be better even if it gives up some working distance and field of view.
I'm still not sure how 3 diopter extrapolates to X magnification but I have a hunch a bit more magnification would be good.
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Update: found this:
http://www.blaxalloptics.co.nz/magnification-facts.aspx- my guess is that a 5-7 diopter or maybe a 3x magnification would be good - helpful enough with viewing and still leave enough working room to solder.