Yes it is, but its late and I may have forgotten something.
Just to add some discussion into the mix:
If you have an U/S APU and have a generator failure on takeoff during in low visibility procedures - you may well stop where in other situations you wouldn't.
The reason being that you wouldn't have two sources of electrical power (excluding the battery), so you couldn't autoland.
If the APU is U/S and a genny fails, then you have to land ASAP (only 1 source). If you have a genny failure and can use the APU as a second generator, you can continue.
It would have to be really bad day for both the gennys and the APU to be broken.