My only solarforce is an L2R and I like it pretty well.
It's very solid - one of the better quality lights I have by look and feel - and there are lots of upgrades possible with various battery / dropin combinations , but there are some things to consider.
first, which module/dropin are you going to use? Your question about the tint as the cells fade would depend on what led module you're using.
If you're using AA cells, you'll want a low voltage dropin. I'm using the older solarforce .8-4.2v 3-mode XRE, and have 2 issues with it: 1) noticeable PWM on med/low, and 2) ringy beam. There are other dropin options -- a newer XPG from solarforce (I have no idea what the beam and PWM are like with it), or other low-voltage choices. Some very popular dropins are from Nailbender, but they're not compatible with the L2R host.. I think they short against the front end of the battery tube. It should be possible to fix that, but it's something to keep in mind.
I know there's a recent thread about L2R dropins... ah, here it is.
Impulse buy! P60 host... need drop-in recommendations!
Some people have mentioned problems with the tailcap/switch. since it's a narrow AA sized tube, the switch is apparently not interchangeable with anything else out there (I'm sure someone will correct me if I'm wrong) and I know I've recently read threads containing complaints about the switch going out. I don't think it's common, and mine seems fine, but there you go.
I don't want that to sound all negative. I really do like my L2R. But it isn't perfect :) Hope this helps
-John