I need to replace my chamberlain chain drive. 1/2 HP is enough for my metal
2 door garage door.

I want it to be quieter, so that means belt or screw. Don't have preference
to either. $200 is my spending limit. I want to be able to get it from
HD/Lowes/Sears. I've been pointed to:

Chamberlain Whisper Drive
Genie Excellerator

I assume the basic features (2 control, optical sensor, smooth stop/reverse)
are all the same. So I'm curious about little extras (disabling remote,
backup battery, etc). And just the general overall quality of the unit.