Which CREE drop-in? CR123 or RCR123?

Getting ready to squeeze the trigger on a CREE P4 drop-in for my Surefire 6PD to replace the SF KL-3 (v3) head I'm currently running. I have been impressed with the KL-3 head, but I'm sheltered and wonder what I'm missing. I'm currently looking at the WolfEyes OP drop-in, but recently found out about a Solatec & Seoul drop-in and wonder if their aren't even more? Of course, I want the best possible option, cost aside.

Also, it seems many of these drop-ins support (2) CR123's as well as (2) RCR123's. I have never had the rechargeable option and wonder what the difference is in output, runtime, and how many times RCR123's will take a charge. Any risk of kaboom? Thanks!!!

Wolf Eyes is a much better unit.

the differance mainly between the battries, the rechargeable one has less capacity (measured in amp) which means last shorter. in the long term, rechargeables are always more cost efficient.