I can't think of any cons regarding the Aeon Mk. lll, unless you just really need more than 160 lumens. It's by far my most carried light. I prefer this size light for everyday pocket carry and the Aeon has never failed to meet any needs I've had. If on the occasion I think I might need more muscle (and if I'm wearing comfortable pants
) then I'll grab my Boss 70, otherwise it's the Aeon.
It has 3 well spaced modes and a quality tailswitch, which I really like as most all my other similar sized lights are twistys. You don't need me to quote Enrique's Aeon page from his site, but all the things that he's put into this torch is what makes it my choice nearly every morning. It has exceptional beam quality with the high cri 219B and parabolic reflector, and the sapphire crystal lens is also a nice added touch. Honestly, if I could think of anything negative about the Aeon I would tell you... Enrique hasn't sent me a check in weeks. Little humor there for ya.
In regards to the CR2... I don't know what your issues might be, but I got 2 UltraFire rechargeable cells with my Aeon and I've had no issues in the 9 or 10 months since. I can't even remember the last time I had to charge one.