there are independent tests.
there was one posted about a month ago via a youtube vid for example.
there's also candle power forums and the various battery geeks throughout there sharing their info.
then there's ...
AkkuDB ... and ...
Battery test-review 18650 summary
so far all independent tests i've seen add up to 4 major contendors that take the cake in the power output department.
there's the sony vtc5 and the samsung 20r
these two seem to have the best power output and voltage holding power during their output curve.
then there's the AW 1600mah and the sony vtc4
these two round out the top 4 and there's a slight margin in voltage staying power under heavy loads.
out of the 4, the vtc5 gives the longest usable discharge per charge.
special notes;
1) under a constant 20 amp discharge, the vtc5 sky rockets in temps capable of obtaining temps up to 20°C above it's 60°C rating. under higher loads, this temp can go up significantly. the vtc5 can be a hot plate in your pocket under a hard short situation. though, that doesn't detract from it being the best battery for a sub-ohm build.
2) all AW cells are individually tested to meet specs and will be the most consistent batteries on the market.
efest cells are bad, mkay. they've consistently tested to have inflated specs in the amp output and capacity departments.
now what you would need to find out is if there's any reports of any of these cells not fitting correctly in your intended mod in your intended configuration... and whether you're going to need button tops or flat top, or if that matters for any mod you're looking into.