We have found through testing that the EF3-4 preforms only marginally better then the EF3-3. Maybe
@fireanimal can chime in with some numbers. But the minor levels of distortion differences we are talking about are not, I repeat not sonically detectable with the human ear. So please don't worry. Build the version that suits your needs. The monitor differences can be due to less beta droop in the output stage due to more current carrying capacity of the output and less load on the preceding stages.