Although the post title says "best" I believe maryc137's question was what is the "easiest".
I was replying to that.
"Is there is a different brand of test kit that is easiest to use?"
Comparing FasTest to Salifert - I believe IMO that the Salifert is MUCH easier to use, and IMO give you better repeatable results.
Not the most accurate, most expensive, most sophisticated, high tech, lab quality, or the most difficult to obtain.
The easiest - compared to FasTest is Salifert - Hands down !
There are many better test kits available as mentioned, but normally not within the budget of most typical reef keepers.