
I somehow managed to never have one of these threads in my forum.
I'm not going to get into this debate or engage anyone, but I'll gladly through some points in!

My battery manifesto:
1) 9 volts is 9 volts no matter the source that 9 volts is coming from. Otherwise, it wouldn't be 9 volts. (So sniff this.)
2) If you want squishy dying battery tones: starve knob, or starve pedal. That way you can get--
and set--dying-battery tones.
3) I've heard the argument that batteries "can last yearrrrs in fuzz pedals"--oh, unless you leave your cables plugged in overnight.
____a) Have a bunch of pedals on a pedalboard? Make sure you unplug
every single patch cable when you're done playing!
____b) Yeah, unvelcro them all so you can pull those plugs...oh, don't short out your Gerorge L's by yanking them around every day.
4) Most effects enthusiasts/performing-musicians eventually mount their pedals on a board, for ease of use/mobility. Most couple that with adapters, whether One Spots (more than sufficient) or advanced individually grounded power sources.
____a) Noise: In a properly grounded, florescent-free room, I dare you to find a meaningful noise level difference between 9v and even the One Spot.
____b) Reliability: I've had far more letdowns with batteries than I've ever had with adapters. Concerned? Just buy a backup One Spot for 20 bucks. You're still saving money compared to batteries for all your pedals.
5) Not a big deal, but it
is some extra messing around--for a feature most effects guys don't care about.
____a) It cuts out using two different jacks, cuts a couple minutes of work, and cuts a couple dollars of cost--which I pass along to the customer!
____b) Include a battery clip and no battery? Tried that...and started getting emails (from guys who weren't using batteries anyway) asking why something is rattling in their pedal.
____a) My sales didn't slip at all after ditching batteries. Seppuku's sales didn't slip at all after ditching batteries.
6) Then...after all of that...you can consider the environment. If you want.