Well, having spent some time operating a 12VDC system last year when I moved into some shacks, I will say that I find it a lot more convenient to run 120VAC.

I end up converting stuff anyhow, because all my loads run at different voltages- even though I had my lights, vent fan, and heater fans running on 12V I still ended up having to change voltages for most of the loads I wanted to run, or generate a AC to to charge my computer and run a rice cooker.

Not to mention that running anything that draws any real power quickly needs a much thicker wire at 12V. So you're either needing to run higher voltage DC than all your loads for distribution and then lowering the voltage when it gets to the device, or you simply can't draw much power.

Not that you can't have higher voltage DC; with my newer system the line from my solar panels to my charger controller is around 350VDC and I can use 10awg for that... but none of the loads I own that draw much power (saws, instapot, rice cooker, hammond organ, tube guitar amp) take DC :D