Here are some coverage maps I made with RadioMobile.
This depicts coverage between two hand helds in here in Mineral Wells, TX.
The receiving station that the plots are drawn around is in the relatively flat center of town.
The parameters i used are:
VHF frequency 154.6
UHF frequency 462.6
Transmit power 2W VHF, 5W UHF
Receiver threshold -107 dBm both bands
Antenna gain 0 dBi both bands
Antenna height above ground 1.5 meters
No feed line losses
First for reference is a steet map. The map is 12 km high x 12 km wide:
View attachment 36414
Next is the ground elevation:
View attachment 36415
Next is UHF coverage at 5 watts:
View attachment 36416
and finally VHF coverage at 2 watts:
View attachment 36417
This shows that with all parameters equal VHF should cover better.
I don't remember off hand what the real life gain is on a hand held with no ground plane or counterpoise is but it is probably way less than 0 dBi and probably even less on VHF because of the difference in antenna physical size vs. wavelength.