I went with the Tekkeon MP3450, I already have one and use it to power all sorts of things from Laptops to recharging other batteries. I have run the 619AH on the Tekkeon for over 3 hrs with still more power to go. I like the choice of power settings available and adapters that come with it…
http://www.tekkeon.com/products-mypowerall.html
http://www.tekkeon.com/products-mypowerall.html