I've read through the thread, so will add my 2 bits...
(I've had a
Rutland 913, and now have a SilentWind)
First, A LOT has changed since the 10 year old Practical Sailor article.
There are
cheap, noisy units, there are more expensive units that are generally quieter. (IMHO, the Rutland and SilentWind are the 2 quietest brands I have come across.)
They all vibrate at some speed. You can use rubber mounting pads to minimize the transference of vibrations to the
hull.
Some units have brakes that engage to stop or restrict rotation. For example the SilentWind will brake in winds above 32 knots automatically. There is also a switch to stop/retard rotation. This is a great
safety feature. (BTW...this is one thing I specifically did not like about the Rutland 913. It was very quite, but it had no electric/electronic break.)
Unless you mount all your
solar panels above your
mast...you will have shade on your
panels at some point (of course it is best to minimize the shading, and buy good
panels that are not as temperamental to shading).
Peter O. said it best...if you are in an area where sunlight is limited but there is wind, you still have energy going into your
batteries. Making long passages you will have energy going into your
batteries 24 hours a day (unless you sit and bobble in the doldrums).
Virtually all new units have good controllers that show outputs (and some with bluetooth outputs to device software).
Someone mentioned drag. I'm not really sure how many cruisers are really worried about drag or windage. I have
solar panels on an arch...that's a hell of a lot of drag and windage; especially when the
bimini is up. I have panels mounted on my hard
dodger. That's a lot of drag and windage. I have 2 panels on rails along the
cockpit....they create a lot of windage when they are down, and probably some drag when they are up. Seriously...I don't care. I would venture to say that a 200 lb man standing on the foredeck adds more windage and drag than a
wind generator mounted on a pole on the stern.
My recommendation would be to find boats in your area that have wind generators, sit on the
dock next to them on a windy day 10-20 knots and listen. If the
boat owner is there ask what model year the unit is, and ask if you can see the controller output (in SilentWinds' case, I can pull it up on my iPhone).