I've only ever had one good amp and its still does the business for me. It doesn't need a noise gate, it has lovely cleans, crunch and does all that evil stuff that the bloke downstairs approves of. To get a good lead or crunch tone just watch the presence, treble, gain, use the mid boost/cut and speaker damping.
I used to be clueless when I first got it, had everything dimed and it sounded like shite.
I've still got to treat it to a set of Tungsols in the pre & power amps. Soon.
As for amps that I didn't like that I've owned. A peavey backstage. Load of old wank.