a good place to start for reviews are, in no particular order,
http://ledmuseum.candlepower.us/third/u2.htm,
http://www.cones-stuff.co.uk/Surefire%20U2.htm, and
http://www.flashlightreviews.com/reviews/surefire_u2.htm.
i think general battery life is on those sites, and the good thing about the U2 is that its body is (usually) wide enough to accept 18650 li-on batteries. These are rechargeable lithium-ion batteries, and provide "free lumens" at the very slight cost of about a 10% drop in brightest output (barely noticeable by the eye). i say "usually" because the newer U2s seem to have plastic inserts in the bodies which prevent the use of the fatter 18650 batteries and require variable amounts of effort to remove them. this will mostly be a concern if you plan to use 18650 batts in your U2 though.
check around the dealers and B/S/T sections of this forum. you can probably find better prices around. in the dealer's section there is a sticky thread by GreenLED called "CPF Specials ..." you can find a number of deals there. I recommend either OpticsHQ from the CPF Specials thread, or oldgrandpajack from the B/S/T forum.
one thing to keep in mind is that there has also been variable QC issues (just browse the LED forum and look for U2 to find the threads) discussed here, with issues on the LED tint/beam, tailcap clickies, plastic sleeves, etc. for that reason alone, one option might be to buy a 2nd hand U2 from the B/S/T forum from someone who can confirm the quality of the U2. Granted, if you buy new, SF will take care of any issues you might have, but if you buy 2nd hand and can get a "good" light, then that's one service you don't need to go through, and you still will have the SF "if it breaks we fix it" guarantee.
a good number of other users also have U2s and will have posted their impressions etc. on the U2. in my sig link i have a modest page with standardized/comparable beamshots of several of my lights, including the U2 if you'd be interested in checking it out =)
hope this helps =)
Edit: i agree it's a bit hard to search for the "U2" or pretty much all other SF lights and a good number of other lights, but it is possible to try searches on SF*U2 or Surefire*U2 or U2*Ultra or something like that. not optimal, but well, it'll have to do =P