What sounds best integrated or separates?

As Greg says, it is very price dependent. A high-end integrated will better budget seperates.
I would take a Creek Destiny integrated over a NAD 162 preamp 272 amp any day.
Not knocking NAD, they make fine products, but are for the more budget minded.

It totally depends on the amp(s), stereo, room, listener, etc.

Arthur

I agree 100% with Arthur. Add speakers and budget to his list.

There are some exceptional integrated amps: Ars Filarmonia, VAC Phi Beta, Jadis...

They don't necessarily take a back seat to any separates if matched properly to speakers and room size.

Integrated separates.

To manufacture large power separates is less costly than same with large power integrated due to the power supply complications for preamp and output section of the amplifier.