Being a fairly new owner of Schulze 6-636, I want to jump in with my 2 cents.
I, too, sold my Alpha4 after I converted most of my fleet to electric power. Charging a 2400mah pack with Alpha's 1amp max is just too much for my patience.
I first bought a Supernova charger for $110 which worked really well, but I needed something to charge higher cell count. I wanted to get the isl8-936g, but waited too long and Euro got strong enough to make it too expensive. So I bought a 6-636 instead.
Great little charger. Just plug battery in and it does the rest. Pack is barely warm after fully charged, which prolongs the life of batteries. And I noticed it can push more mah into the cells than my Supernova can.
Only thing I don't like is the programming method. To reach some menus, you have to hold certain buttons on powerup. I don't like to disconnect and reconnect power just to program.
I didn't get the pc interface, but apparently it's upgradable later on. It would be nice to have, but I have enough cables running to the charger already.
You can read more about them at:
http://www.schulze-elektronik.com/isl6-e.htm