I should have mentioned that the OpticsHQ/TLS multifunction tailcap draws power even when the light is turned off -- about 0.5-1 mA according to OpticsHQ. The Uniq tailcap apparently also draws about 1 mA even when the light is off (I don't have any hands-on experience with the Uniq, this is based on CPF posts by others). I would estimate that with AW RCR123A cells, you'd get about 3-4 weeks of shelf life with the OpticsHQ tailcap, shorter if you actually use the light during that time. You can always back out the tailcap by a partial turn to disconnect it electrically. But then you have to re-tighten the tailcap to get the light back into operation.
A CPF search seems to show that the Uniq may not have identical performance with all Malkoffs. See
http://www.candlepowerforums.com/vb/showthread.php?t=199281
Some seem to have good luck, others get the so-called "moonglow" problem. I've seen the moonglow problem with the OpticsHQ tailcap as well, when using Deal Extreme 6090 and 11836 drop-ins. In post #17, the Uniq tailcap also got stuck on high with a Malkoff, as well as getting stuck in moonglow.
The Uniq also apparently always comes on in low first, if that matters to you.
These two links have some additional info:
http://www.candlepowerforums.com/vb/showthread.php?t=216888
http://www.candlepowerforums.com/vb/showthread.php?t=201722&page=2