I have a Go Power 300w PSW inverter. I really wanted a Morningstar Sure Sign 300 because it has no fan, but the cost difference was just too much for me.
But I've found that the fan doesn't come on in normal power usage so I can leave it on all night to charge phones and stuff in silence. Yes, direct 12v may save a quarter amp. I've got plenty of amps and like the simplicity of plugging things in like at home (as the electron manager of my family, I like to keep it simple).
My criteria was good reviews, cost, and heavy weight. Roughly in that order.