Just for the record, people do not dose EQ high enough. It's something like 60% ester.
When dosed correctly it stands on its own, Primo does not compare if we are discussing growth potential (fully aware that's not the question in the OP).
With Primo, if I let my E2 drop too low, I feel all the symptoms of crashing E2 with an AI.
With EQ, yes it drops my E2 but it's not the same feeling as long as I have a decent dose of testosterone in my system. Between the Testosterone entering, processing to some E2 and then being reduced from EQ I seem to get just enough E2 to the right places as it comes and goes. Thus, the low E2 readings on labs don't actually reflect the same low E2 environment and side effects that Primo or AI's create in my experience.
All that to say, I believe EQ is superior for E2 control (if it has this effect for you), while also contributing more to growth.
I will only use Primo now, similar to
@Sector mentioned, very low dose 100-200mg and only if I try to push my Testosterone very high and for whatever reason EQ doesn't control the E2.
The addition of Tren could also justify a low dose of Primo, as it seems to make me very estrogen sensitive.
Edit - Re reading this, I suppose black and white, Primo is stronger at reducing E2 for me. I still rate EQ as the better option for the above reasons though.