There are already way more than enough excellent available choices for regulated mod users so, logically, my vote has to go to a 25A CDR 20700 that hits about equally as hard as the Samsung 20S at least, but that, at the same time also, runs for more than just a measly 15% longer than the Samsung 20S so that we can then FINALLY start using all our expensively bought 20700 tube mechs how we SHOULD have been able to use them of course. 
