Personally I avoid separates when possible, even if they cost the same, because the multiple power cords escalates the possibility of ground loops. Also the improvement (generally) of lower noise floors per device, at least in theory, often gets thrown out the window if every device in the chain doesn't have a variable input and output level controls so I can optimize the gain structure from device to device.
A common similar problem is people who buy outboard DACs—because they're in vogue these days—and then muck up the performance of their existing AVR or prepro because they suddenly have to engage its mediocre ADC (say because they rely on room correction and bass management, nearlly always done digitally) whereas when they previously used their optical disc player connected digitally that noisy step was bypassed.
