There is a discussion on the yahoo group re the Yaesu VX-7. It is that the
silver color has reflective properties and in consequence inhibits a larger
RF signal being transmitted thought the same power of radio.

I think that in the same turn, a silver color of receiver will grab the RF
going into the radio and not let it reflect back out and thus 'sponging'
more RF signals and making a better radio all around.

One member said that the rubber antennas are better as well since during TX,
the RF signals bounce off the antenna and thus travels farther.

I dunno... sounds good to me