I bought a ICOM a few year back - it stayed with my A&P for almost a year.
First time I had it with me was flying back from St. Barths after the annual - alt belt snapped - I did not notice as the radios (Collins with nixy tubes) kept glowing and my annunciator is not that bright - 60 miles out from Barbados seems to be where it happened - no answer when I tried to call approach - by the time I realised, I thought a ha the hand held so dug it out, by then I was about 35 miles - my transponder of course had gone off - seems I spoke with them just as they were preparing to call out the coast guard to go look for me.
It was very loud in the plane - but holding it too my ear I could make them out - uneventful after that, so yes it worked and probably saved me lots of grief - well worth having.
I tested it once at 5,500ft it worked out to about 45 miles.