I did a lot of research on stains, most performed dismally including several I personally tried. The solid colors and semitransparent act more like paint and hold up better.
If you want a transparent clear or transparent tinted (the best choice because clear ones have less UV protection to prevent graying) I would recommend Sikkens Cetol 1 (base coat) with Cetol 23 (top coat), Sikkens Log & Siding, Shuco Transformations, Continental Weatherseal. and maybe Permachink Ultra. There are probably other good ones out there, but there are so many bad ones I would only use it myself if I saw real test data or had personal experience myself or from someone I trust(a high end painter) You can also use 3 coats Cetol 1 in place of the 1/23 combination. DON'T use Sikkens SRD-it doesn't hold up nearly as well.
All the good ones are oil based from linseed/soy oils so the raw materials are enviro friendly but require paint thinner for cleanup. The water-cleanup ones are less enviro friendly to make but don't do as well. If it holds up longer so you have to do it less often, I think that makes it more enviro friendly!
Here are 2 good links-the only visual comparison test info I found where a manufacturer put their money where their mouth is:
http://site.ozarkloghomes.com/pdfs/t...tionreport.pdf
The Continental Products Company - Your source for Log Home and Industrial Coatings including - Log Home Paints, Log Home Presevatives, Log Home Stains, Log Home Sealers, Log Home Maintenance Products, Log Home Coatings, Log Home Floor stains, Log Ho
Craig