I agree with you that the quality of the water used is extremely importance as is any contamination after making the silver solution. However, I beg to differ strongly when it comes to differences between silver solution machines and particle sizers. The quality of silver solutions differs greatly among various machines and particle size is of utmost importance.
There is no way that the simple 9 volt battery set up proposed by Beck produces anything close to the quality of a good Silver Puppy, SilverGen, Utopia Silver Silver Bullet, etc. And there is no way that virtually any home unit can compare to the very best commercial solutions in either ionic content or particle size (though I must state that I totally do not buy into the 15K ppm single atom hype of the one company and their products).
Particle size is important because the smaller the particle, the greater the surface area per ppm of silver content. Think in terms of the surface area you would get from filling a 50 gallon drum with basketballs (large particle silver from cheap units and outdated companies), softballs (better home units and fair to average commercial products), pingpong balls (better commercial mostly ionic silver products) and BBs (the very best, mostly colloidal silver products from Utopia Silver and Mesosilver).
The basketballs will have the least surface area by far. The softballs will have several times more surface area than the basketballs, the pingpong balls even greater surface area and the BBs a huge amount more surface area - hundreds and even thousands of times more than the rest. Notably, the smaller the particle size the easier it may be able to get to places than the larger particle sizes.
Two real life comparisons should prove my point. First, check out this post here on this forum where a member compared plain water, homemade ionic silver and Utopia Silver's Advanced Colloidal Silver on three slices of bread which he misted and sealed in Ziploc bags.
"At roughly two weeks the water and ionic bread slices had grown all sorts of fuzzies and green stuff, with the ionic slice being worse overall than the plain water slice. At this stage I tossed both of these out.
I'm currently about three weeks into the test, and the bread slice with the Utopia colloidal silver on it has yet to show any signs of growth. It still looks exactly like it did on day one."
Then there was the post on my Yahoo forum where a member said that she had been using a prior SilverGen model and decided to upgrade to the 48 volt Silver Bullet. She found that the Silver Bullet produced better results than the SilverGen but that the best results of all came from the commercial product.