Are integrated amps technically better than separates?

Separates always will be better, technically. Also, separates give you opportunity to optimize amplifier with speakers, without changing signal processing part. In addition to amp flexibility, you can plug active speakers directly into preamp. Moreover, class A and high bias class AB amplifiers running very hot, which is devastating for preamplifier part of integrated, and that will shorten preamp life. 

@audition__audio: if your power supply, AC outlet before/after including,  is bad, comparing separates to integrated is kind of lower improvements pareto thing. 

Agree with “erniesch", his statement is 100% correct: "Never mind that just inside the wall is the cheapest copper lines the contractor could buy.” Last two feet power cable 10 or 18 AWG difference is drop in the ocean, if power lines inside house are bad.