I have been using the WF139 for over 3 years now with no problems. With the cigarette lighter adapter, I can carry the charger in my truck for charging during travel, if need be.
I also have what I consider to be the gold standard of chargers: Schulze. Usually charge my 26500s with this charger. The only thing is that the Schulze chargers can cost over $300 new. I got mine used off of Ebay for a whole lot less than that some four years ago. Bought a used Mastech power supply from Ebay as well for a song. But this type of charger is less portable than the WF139; hence, it stays on my workbench in my garage.