that's good advice by koyotee. What the BLF community has done here is make some of the best reviews and dialog on the net regarding dive lights (of course regular lights too). And you can find the best deals.
No, that light is not a good deal. Also, see this post. Same light, sold by different seller. - ok Ramblings beat me too it.
I highly recommend going rechargeable Li-ion, unless you travel a lot to dive, then you want batteries that you can find oversees - Alkaline.
LEDs: the Cree XM-L / XM-L2 is a really good emitter especially in lights with a bigger head, like a primary light or canister light. The LED puts out ~1100lm at Cree's recommended max ampere (3A), which light manufactures rarely exceed.
Many many dive lights use an XM-L.
The Cree XP-G2/XP-G is another good LED for dive lights. Better suited for the smaller lights. It throws well, but has around half the output of an XM-L at recommended max (1.5A)
Some use Cree XR-E which you'll hear in the 100+lumen range. Like the XP-G they are good for throw and cutting through muck, but even less lumens than the XP-G.
Most Chinese dive lights I've ever seen use some variation of a Cree LED.
Only a few use other LEDs like Luminus, for example Hollis (a canister light) and Light Monkey (can light)
Lumens: most lumen numbers are false. There are only a handful of dive light manufactures that use a standard like ANSI FL1
e.g. Xtar (read bottom) and Pelican. I always want to know OTF lumens... how many actual lumens are coming Out-The-Front.
Sometimes if I know what the measured tailcap current is, then I can estimate how many OTF lumens a light will put out.
Then candela or lux will give me an idea of how well the light "throws"
Recently I asked Brinyte what their ANSI rated lumens were for their dive lights. And because they have their own integrated sphere they gave me the figures (posted here). At 0:25-0:30 sec. into video you can see them using the sphere (youtube).
recommendations from Dive Matrix. And recommendations from here at BLF. On both of them I mention the new Stubby Impact light from DRIS.