Advantage is the P1900 will give your screen clean, regulated power and prevent those nasty spikes in voltage.
Having said that, I plug my Xenarc directly into my lighter socket because it came with a lighter plug and I presume they wouldn't do that if the product couldn't take it. I'm probably wrong, but so far, so good.
In reality, I'm also getting a mini and will probably change this when I install the P1900. It seems a small price to pay for some insurance for my $$$ screen.