One thing to be aware of if you plan to power it with an external battery is that R44 uses (center-neg.) and (sleeve-pos.) which is reverse polarity from most devices.
Definitely something to keep in mind as hooking it up to a power source with "correct" polarity can blow the tiny non-user-replaceable fuse on the circuit board.
Aside from that little twist, I personally can't recommend the R-44 enough. I've used mine pretty much constantly for well over 4 years, run it off external power sources and internal batteries, and have never had a single issue with it except ones caused by me. A reliable, great-sounding deck that I wouldn't hesitate purchasing another one of if I needed to.