That's a completely different kind of torch, running from a single 18650 rechargeable Li-ion battery like the one it comes with, it can't run on 2xAA batteries. Whether it's worth the extra cost, that depends on whether you need the additional brightness, and part of the increased cost is the included cell, wall-charger and built-in charging functionality.
Personally I wouldn't say it's worth the extra, I have a couple of lights that are that bright and I hardly ever have occasion to use them, they're far to bright to use indoors unless I need to light up the entire room by shining them at the ceiling, and they're too big to carry about on day-to-day stuff. If you're going exploring you might need the extra brightness possibly, but 250+ lumens is still plenty bright enough for 90% of needs.
The caveman is only available from Shiningbeam themselves, but fortunately they are US based so you don't have to fear the dreaded "my thing didn't arrive, halp" email rigmarole. I've dealt with them a fair few times and have never had any issues, their CS seems to be excellent.
