Choosing the "best" site is often a matter of opinion and tastes. The site that I have made the most with per article is howtodothings.com, however the 100 articles I have there are no longer under my copyright. With that and the fact that they have changed how they make money and not increased my opportunity to make more means I have no desire to continue writing for them. They also have editors and some have wanted me to change the intent of my article based on their personal opinions...so I don't writ there.
I write a lot on Helium. It is definitely one of my least profitable sites, but their articles are really really easy to write.
Figuring out the best place, is going to be up to you.