I use the 50/60A versions of the Multipole connectors (probably the ones you have there are Multipole) on CrazyBike2 (in my avatar), some of them harvested from UPSs.
They're used on the battery and motor side of the controller; I actually just used the existing wire harnesses already crimped in the connectors, and bolted them together and sealed the connections with heatshrink on the ones I could, electrical tape on the others. I'd've lap soldered them instead (actually interwoven-soldered) but I wanted to be able to easily change how the power system was set up, so I just bolted them.
I was using them on DayGlo Avenger and The Velcro Eclipse, too, but at the moment only TVE still has them, as I had too many connections I needed to make disconnectable and still inter-mateable on DGA during a recent rewire, and not nearly enough salvaged Multipoles to do it with (plus the size was an issue with limited space inside the enclosed area I now have). I'd rather be using this type on everything, if I had enough of them that would inter-mate. (they are keyed connectors, so only the same color will plug into each other, except for the gray and black, which are interchangeable).
As for when they're useful, well, that depends on what you have on there now. If your phase wires are thick but your connectors are small, and not rated for the current going thru them, then you could use the andersons on the phases, which tend to have higher currents than the battery side of the controller. If they are 2-contact Multipoles, then you'll need four connectors (two for motor and two for controller) and one contact will go unused so you can just leave it out of the housing if you like.
You can use them for battery connections, too, although at this time you probably don't need something rated that high. They are a very secure connection, unlikely to ever accidentally come unplugged, and can easily handle the spark of connection and are self-cleaning contacts during disconnect/connect cycles.
