I think the problem here is that the term 'good equalizer' in this day and age is a bit oxymoronic. Back in the old days, Harmon Kardon had a preamp call the Citation One, which employed switched tone controls, i.e. the tone controls were built up out of rotary switches. This allowed them to be truly flat when set to the flat position. I've not seen a modern EQ unit that had that sort of attention to detail.
I've had my hands on some fairly good units, both the analog and digital Accuphase units, which are arguably amoungst the cream of the crop in equalizers. Despite serious room anomolies that the EQ units could correct (somewhat, there was a bass node that they couldn't touch), the system sounded remarkably better using no EQ at all... by 'better': more impact, greater soundstage, more detail, smoother overall sound...
I've had my hands on some fairly good units, both the analog and digital Accuphase units, which are arguably amoungst the cream of the crop in equalizers. Despite serious room anomolies that the EQ units could correct (somewhat, there was a bass node that they couldn't touch), the system sounded remarkably better using no EQ at all... by 'better': more impact, greater soundstage, more detail, smoother overall sound...