Cross-loads are harder for a PSU to deal with because voltage is being concurrently applied to different rails at one time. Think of it as loading up your CPU, graphics and peripherals all in one go - a worst-case scenario.
Cross-load 1 puts almost all of the capacity down the throat of the minor lines while stressing the 12V line(s) with a couple of amps. The reverse is true of cross-load 2.
It makes sense to compare the be quiet! to a supply in its class. Also coming in at below £50 is the Xilence Performance A that we spoke about on the previous page.
Our personal standard is that supplies should not over- or under-volt by more than two per cent, in either direction. Both manage to pass this informal test just fine.