It's a shame that the most vocal seem to be the few who've had problems but I guess that's the nature of forums. The battery for the Arrow is just an iPod 4G battery so it's not hard to replace. Can't blame the amp for poor charging habits as the same thing happens to any iPod/PMP with a lithium-ion battery that isn't properly charged.
I've been using my 1G for nearly three years without battery (or any other) problems. I now have a 4G and it's an all round incredible amp. I've only heard this level of SQ/clarity with the Pico Slim but the Arrow works well with IEMs
and full sized cans. It's form factor makes it like I'm not even carrying a portable amp when using it with a PMP. It just folds into my iPod leather"wallet" along with the iPod.
iPod + Arrow + case = 1" thick (1.2" incl. the middle retaining strap)