None of the visual sound pedals are true bypass. They do however have a reportedly good buffered bypass.
You guys are mixing up the two problems. Is the hiss you are talking about when the effect is ON or when it is bypassed? Hiss during the effect can be considered quite normal. Hiss during bypass is horribly unacceptable.
True bypassing the the visual sound pedals is not as simple as a drop in. The DPDT footswitches are soldered onto the PCB so there will be some work involved.
As for the hiss during some of the effects, I don't have much of a solution for that, it's usually part of the effect's inherent weaknesses. The way people try to overcome the noise is by replacing the capacitors and resistors with better grade ones, but it is a highly involved mod.