.. one-man brake bleeder kit ??..

I'm getting ready to bleed a newly installed dual master cylinder brake system ..
because of the added time/complexity of doing a dual cylinder set-up, I was looking at some of the one-man bleeder kits on the market >> was just wondering if anybody here has bought/used one of these kits ??? ... and is it better/faster to use a kit that pushes the air to the master cylinder from the caliper .. or draws (vacuums) the air out from the caliper ???

thanks