I have the build your own system, which is heavy on the goal zero- I didn't get the yeti because I don't like the fact that it doesn't use easily obtainable (nor scalable) storage technology.I do like their solar stuff though, especially daisy chaining, and more importantly, storage. So I got 2x 27 watt folding panels, and a guardian. The guardian has a max input and output of 90w (may be too small for some of you folks!), and is not a MPPT charger. How much difference? eh, 10-15% difference, at best in conversion. But I can hook up the guardian to a cigarette lighter, to charge off the car (at 30 watt), or to a wall (at 80 watts?). Its a very flexible system for me, depending on what my needs are, and is vehicle portable. Best part is, I am not tied to one battery, I can use any battery I wish. Agm, flooded, deep cycle, or even the starter battery.