I been considering the emg bqc or the aggie obp 3. I got time to decide so it will be a imformed decision when I do it.
From a purely technical standpoint I prefer the OBP-3 to the BQC.
The OBP-3 is designed using BOTH JFET and OpAmp components and offers the attack and clarity of a JFET circuit with the warmth and color of the OpAmp.
It is VERY similar to the USA 18v circuit.
This issue (which pre is better, etc... ) falls under the same category of discussion that the "which bass is better" question presents.
As an individual musician with your own tastes, influences and the tone you want to find/hear in your instrument selections, you really need to try to find as many samples of these two circuits in action as possible and make up your own mind.
Other bassists will have biases and thoughts on this or that, like what I said above about the tech.
But at the end of the day this is YOUR bass we're talking about. YOU will use it to make music for YOU. And therefore ONLY YOU can make the decision which is going to be best for you.
Please always keep that in mind when asking anyone for their recommendations on this or that bass/amp/circuit/pedal, etc... In the end the ONLY opinion that matters is your own.