I don’t know about “performance – wise “, Mike.
BC-348 much easier to determine frequency, better frequency resolution, easier to actually tune around on.
Of course, ARB was limited at high end by the defined top “combat frequency”. ( Interesting Japan’s top end seemed to be 10 MHz and 11 MHz
for crewed combat planes and even very large crewed planes. ) The 348’s crystal filter actually did work – altho many or most nowadays need servicing so it’s not,
as one surplus conversion lamented, just a “high / low gain knob”. Oh also the antenna trimmer, at least on the early models.
-Hue Miller