I can't believe the USCG is gonna stop monitoring 121.5. Isn't that what aircraft ELT's transmit on?

Re batteries, there is an adapter available that will allow the use of more readily available batteries (or so they say).

As for maint/repair, if I couldn't find myself some retired military radio tech who was willing to play with it, I think I would just try any place that works on "HAM" type radios. It all looks like spagetti inside to me, but I suspect that to a radio tech type a radio is a radio is a radio. Or maybe not. Personally, neat as those things are, I think that I would look for something newer and more reliable to bet my life on.

By the way, welcome new guy...