I've been debating replacing my LF2 and going back to a Photon II or Freedom. Interestingly I posted a poll on edcforums asking if people carried a light on their key ring and what kind - and while there were some AAA fans the majority carried Photons or Fauxtons or the like - a surprising result given the amount of bits spilled over the perfect key ring light.
I think the edc perspective is that for most people, myself included, the key ring light is a backup in case your primary edc fails, and to get you to another more powerful light. Given that role, and the size/weight factors, it is tough to beat a Photon. I hate a bulky set of keys and already have more on mine than I'd like - car key, two house keys, an REI aluminum whistle, my LF2 and an SAK minichamp. I'm really thinking about moving to an Alox Classic SAK and a Photon to decrease the weight (I just like having all the Minichamp options but realistically use the knife and scissors 90% of the time).
So - as flashaholics we all love a cool light and in all honesty, the LF2 was the first light that had significant enough advantages for me to move from the Photon II I used to carry - and I've tried Arc AAAs, a 3mm drop in Solitaire and a Gerber Tempo. The LF2 programmability, the excellent floody beam and easy operation make it an excellent light with multiple battery options, etc...
But if you're going with 3 or 5mm I can't see a huge reason to do anything but a coin cell light, particularly one as flexible as the Freedom.