IME, the bass and trebel controls are pre-drive since it gets more distorted if you raise their levels and leave the drive level the same.
IMO, the EBS is a more compressed sounding pedal than the SFT or greedtone, especially when you use alot of overdrive. of the three, the EBS seems to be the most capable of being uncolored when not using any overdrive, but only in the 'flat' mode. in the standard and tubesim modes, there is a boost in the midrange, but in those two settings the low end isn't getting clipped so just the mids and highs have overdrive. in the flat mode, the full bandwith is running thru the overdrive, so i find the flat mode to be great when using lower amounts of distortion.
i actually got the EBS to sound exactly like the SFT in the flat mode, but the SFT allows treble and bass boost and cut, whereas the EBS doesn't.