I don't think any is the Best. I just make sure it says it is pure lye, meaning no other ingredients are in the mix. Food grade only matters if using it for food preparation, which I don't, so I'll buy whichever one I can find for the most reasonable bottom line cost & speed of delivery.
I have purchased a few different brands, both while at home ordering online and on the road when making soap while traveling. No end product (soap) differences noted with any of the different brands over the years in my experience, although I don't particularly like the large flakes some come as. But I learned to get used to what I get when I open the bottle.
I like the convenience of online ordering and really enjoy taking advantage of sales that come along with free shipping, which I often find give me the best 'bang for my buck'. I also like buying products from vendors who deliver (at no additional cost) directly to the soap conferences I attend, which Essential Depot does if ordered with that stipulation. I also really like the HDPE bottles that the Essential Depot lye comes in with a very secure child-proof lid, especially because they're a good size for my elderly hands when full of MB lye solution. So I have purchased from ED more than any other vendor, and with these types of savings, their products do end up being competitive. Speaking of the lye bottles, even though the Lye Guy's website now says the bottles will be sent in better quality HDPE bottles with child proof caps, the picture still shows the PET bottle that it came in when I used his product; I feared it would crack too easily & I certainly could not use it to store lye solution the way I can in ED's bottles. If the new bottles really are what he's selling his product in, that would certainly make me rethink using his product.
But I have also purchased at Hardware stores, Tractor Supply Company, etc. while traveling throughout the US. The soaps all turn out just fine no matter which NaOH I purchase. I have found the best price for NaOH in ACE hardware stores versus the big box stores, but tend to drop in at TSC because they are almost always visible from the Freeway making them a more convenient stop while traveling.
KOH, of course, I have to order online; I've never seen it on a shelf in any brick and mortar store, although I don't get to actual soap supplier b&m stores, so maybe I just don't go to the right places.
