I love my JB3... I've run it for a long time now and expect to have it for many years to come even as a backup unit once I grab something different...
Unless you stealth, the whole JB3 battery issue should be a moot point... There are tons of alternaives out there to run the JB3... I currently run a VR-box and 9V battery and am able to not only run my JB3 but also my UA5 off the same 9V battery for probably 4-6 hours easy... Although I initially bought a VR box, I've since built a box for a friend and trust me, it's fairlly easy to do and doesn't cost alot to build...
JB3's are tanks... They're tuff little(ok maybe not so little) machines... They are tried, tested, and true...
I've recently been running an R09 and I can honestly say that I would never trade my JB3 for one in a million years... Don't get me wrong, the R09 is definitely a nice recorder, I just find that for my use, it has more limitations than the JB3... For one, the R09 does not have the ability to accept a digital in, and although the built in pre/adc in the R09 is made by Edirol, it still doesn't stand up to an external pre/adc...
For me, the only JB3 limitation that I see is it's inability to accept 24/96... But then again, there aren't many bit bucket's in the JB3s price range that do accept 24/96... The h120 is 16/48, the R09 is 24/48, and the JB3 is 16/48... The only one I can think of without going to a lappy or a pda is the MT2496, but again, the MT has had it's share of growing pains(mind you, people have been pretty pleased w/ the latest firmware)
To be honest, I haven't had much experience with the h120, so I really can't say much about it one way or another... But no one seemed to be chimming in for the JB3 so I thought that I'd throw you my 2 cents...