I've seen the "By My Side" guys at shows in Michigan. Funny that two booths down some other guys were suggesting the By My Side idea was nice but expensive. They were demonstrating a simple magnet that is (smartly/sensibly) mounted to a surface inside your car. The cost was significantly less and equally effective.
Is there really a need for a "car holster" to hold a gun with multiple safeties? Something like this seems effective to me..........can't upload pics!?......so here's a link....
http://keeper.mg
About $25 on Amazon. There are other similar and less expensive magnets.
*EDIT* Just realized I raised the dead, perpetuating the OP's sales pitch.