Active or passive mix after A/B box and effects?

[brett]

Hi
I'm interested in this question because it has many options and implications, and I'm not smart enough to work it out*.
I'm guessing that many people figure an active mixer is cool.

Thanks for voting!

* Another motivation for asking the question is that a favourite pedal of mine is a RangeMaster, which loses tone if not connected direct to the amp.

[gez]

I prefer active mixing for all sorts of reasons.  In phasers etc a common problem is output level is affected by what follows due to loading, which doesn't happen with active mixing. 

I prefer op-amps.  They also give you the option of boosting as well as attenuating (smaller feedback resistor than input resistor in inverting setup).  Plus the negative earth effect helps prevents the interaction you can get with passive mixers.