It always depends on the player/amp and the sound that you want.
90% i record without a boost
peavey 3120 for example works fantastic for me without one
It definitely has to be the right amp, but amps that can stand their own without a boost always pull off my favourite tones. I can even run my 7 string through my 6534+ without a boost, it sounds so raw and punchy I wouldn't dream of diluting that with a boost. Some amps, though, just sound better with a boost, or they literally cannot cut it without one.
D tuned here. No boost in front of my Engl Savage.
Engl amps and boosters are not good friends.
I don't like a boost in standard, always sounds a bit too flat and lifeless.
I ALWAYS try the amp with the boost pedal engaged and without it, and see what sounds better. No rules.