I did some reading on the imax and the rebranded versions. (Is the Core-RC UDC20 one too?). It appears that its a chinese knock off of the bantam b6 where they basically copied the circuit board but used inferior tolerance components which means it can't balance accurately and can actually overcharge individual cells.
You can read reams on this here :
http://www.rcgroups.com/forums/showthread.php?t=777717
Don't think I'd buy one of these both because it can damage cells, but also because its straight design theft from what I can see. The bantam firmware even works on the device it such a direct clone!