I have actually used a throttle lock and find them unsatisfactory. With my Kaoko, my speed does NOT remain constant, but varies with the terrain. I use the GS for long trips, including New Orleans, Maine, Connecticut, TOD and hopefully next July to Alaska.
Here are a few arguments/rationalizations for spending the big bucks:
When I am leading a group of friends on a long cross country trip I want to keep a constant speed.
A few months ago I lost concentration and received a performance award for 78 in a 65. Sad face.
I have a mild case of carpel tunnel that for some reason flares up on long highway trips. I am hoping that the cruise control will help with that.
Now I can focus more on spotting f***ing deer!
Life is suffering until you realize that life is suffering.