The only real difference between the lehner and feigaos is that the Lehners are made in Germany and have a screwed on endbell (won't fall off) and the feigaos are made in China, they have a pressed on endbell that is prone to popping off, but getting the rc-monster heatsink solves this, as it braces the motor.

The BK 9920 is a great controller, you can't really go wrong with it, if you want a bit more than 99 amps, you can get the 12020 warrior that can handle 120 amps and 20 cells, but there aren't many motors that can even pull too much mroe than 99 amps, so the 9920 is find IMO.