According to Schiit's "philosophy" in dacs and amp, they believe that a separated dac and a separated amp is more desirable. This is one of the reason why they have so little dac/amp all in one combo. Until they released the no compromise Jotunheim all in one dac/amp. (Not counting in the Fulla)
IMO I would also consider aesthetic value in my personal preference. OCD Either have a stack of the same size so they look nice on top of each other. Or one compact minimalism approach. Having two box of different size or what putting them together beside my Macbookpro is unacceptable for me. (OCD)
But if you are only considering sound quality, then it is another story