Al, I have an old VHF too.... and it works fine... although I could stand to gain back a bit of space by buying a new unit, and I'd get more features... but the real issue is that a new VHF brings more knobs and controls that complicate using that radio for any crew that might have to use a VHF in an emergency.

The existing radio has three knobs... on/off/vol squelch and channel. A new GX1600 has a few more controls... although I note with keen interest that vol, squelch and chan up/down seem to be fairly clean.

But this upgrade is one of those things that can lead to issues if one doesn't ensure simplicity. Take the car radios of today... they do not have a standard interface and often require reading a manual to be understood... old car radios had two knobs and 5 buttons... and they all looked the same.