I personally enjoy having the brightest possible, but in all reality, I doubt anything more than what Surefire offers is good for much more than the "impress your friends" (who aren't really impressed anyway) factor.
That being said, its going to depend a lot on the price of the new P61L as to whether its worth decreasing runtime and spending the money for an extra 50% in brightness.
On the one hand, you like having the brightest possible, but you also show that you understand that there are runtime tradeoffs.
Using the advertised lumen ratings of some of the brightest as being around 225 to 250 lumens, many of us who own lights in that class have come to see that it's really more light than is needed for most situations.
Yes, I'll be using my brighter lights, but I've also come to appreciate that a 120 lumen light (still brighter than is needed for most situations) is a wonderful thing to have when it can come with a 4 hour+ runtime.
It's nice to be able to grab a light and go without worrying about whether you'll need spare batteries or not.
To see how a trend is starting, note that another maker of P60 dropins, Malkoff, has now started offering lower lumen dropins; a 140 lumen one that runs 4-1/2 hours+, and he also offers an 80 lumen P60 dropin that will run for God knows how long.
So I've got a new 6P that's begging for an LED dropin, and a 4 hour+ runtime at 120 to 140 lumens is looking pretty darn good right now.
When I started as a lurker here on CPF, I was attracted like a moth to all the wonderful reports of the brightest lights that could be had, and I've bought a few of those.
But now, I've come to appreciate features of some of these lights that have little to do with having the "ultimate" brightest lamp.