Sorry, but this is an issue I'm particularly passionate about. Apart from the legality of whether these handheld radios are even approved for airborne use, it seems to me that the mindset seems to be "I'm obliged to put a radio in my plane so I'll put in the cheapest one I can find, and if other people can't make out what I'm saying that's their problem".
The radio is the only means we have to tell other pilots where we are and what our intentions are. IMO, you want the best thing you can put in there (within a reasonable budget) and handheld radios just don't qualify. For a start, unless it is connected into the aircraft power, you've got battery life issues, both the charge life and the life cycle of the battery. Then you have the quality of the electronics and the quality of the signal. Finally, most handheld outputs are optimised for the little "rubber resistor" antennas rather than proper antennas.
You've spent so much on the plane, why not protect it with good comms?