What sounds best integrated or separates?

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.

A smart buyer can find high quality separates on Audiogon that when mated together, can outperform any integrated at the same price point. For example, find a Forte 4A amplifier for $600-$700 and a Modulus preamp at $800. There is not a $1,500 integrated on the market that can match this sound. One recommendation: don't cheap out on the interconnect, but keep it as short as your set-up allows, and consider putting a line filter on the cable to kill RFI.

Uraniumcommittee; I know what you mean about integrateds being low in power (so, cheaper) and thus not as good as separates. Do you mean something like these?

Zanden

Audio Note

Or, even my system.

This is a very tricky question. It is all system dependant. What sounds better, a two box preamp and amp, or the four box ASR 'integrated' amp? Many preamps themselves are integrated, having built in phono stages and/or power supplies. How far seperate do you wish to go? The 6 box Aesthetix Callisto/Io with dual supplies? Basically a 6 box full function preamp.
Monoblock amps? Monoblocks with seperate outboard power supplies/batteries? You could have 10 boxes just for a preamp and amp for crying out loud.

It's all relative. 99.99% of us here have integrated to some extent.

John