There can only be one best one:
"The reason for our test hasn't been in vain. We have become a lot wiser about what latex is available. There is a wide sub-top, with all-round products like Joe's and NoTubes. Fast or durable. If you look at the amount of latex per tire, then Effetto Mariposa, Bontrager and Tire Sealant from Stan's NoTubes are the cheapest. For the rest, the results are close together and all products do what they have to do. Yet three of them stand out from the crowd with their head and shoulders. Thanks to its quick seal, the Stan's NoTubes Race Sealant is one of the best in the class. The Peaty's Tubeless Sealant is also a winner, if only thanks to its blue glitters. But at the top of our list (pdf) is Squirt Seal's latex, which surprised us with good results in all areas".