I owned an old L2 (square body) which was a fantastic light. Beautiful white beam. I'd never even heard of doughnut holes back then. I sold it because the new version was supposedly brighter (100 vs 60 lumens) and had longer runtime on low (18 vs 8 hours). When I got my new one, I was extremely dissappointed. Green tint (not too pukey, but it certainly wasn't beautifully white), doughtnut hole, and for some freaking reason, the indicators on the tail cap weren't alligned; all they indicated was that the indicators weren't indicating what they're were supposed to indicate. I sent it to back to Surefire for replacment (they said they'd replace it) and they sent the same light back without any explaination why or why not they did anything with it. I sold it for a lot less than I paid.
I honestly can't say if the new one was any brighter since I didn't own both at the same time, but neither can I honestly say the new one seemed any brighter based on memory and comparison with other lights I owned. Then I learned that the upgrades in Surefire's ratings of some of their LED lights were because they used a different, more accurate way to measure them...and might not have actually even increased in brightness.
If you like your old one, keep it, and don't bother with a new one. I wish I did. If you're concerned about the (supposed) longer runtime on low with the newer model, don't be, and pick up a couple 14760 rechargable lithium ion batteries from AW or lighthound and run them guilt-free. Maybe keep a couple sets of SF primaries in the glove compartment for emergencies.