I've always used Ram mounts until I tried Techmount. Techmount is far better quality.
Another vote for Techmount. I only wish they had a quick release on the arm, so you could remove it when you not using the GPS, and just leave the clamp on the bars.
I did get the quick release kit that allows me to take the GPS off in seconds, but I'm still left with the big plate on the bike.
Powerlet also makes one using Techmount mounting plate, with a cleaner power source.
Put my new Ram mount on the bars of my "09 Road King last week with a Garmin Nuvi. Works great, everything was simple and smooth to install, no vibration at all on road.
Don't have experience with the mount you refer to but I can say I am very happy with the eCaddy mount I put on my Ultra. Can mount it left or right on the bars, nice and solid, visible, and clean lines.