600 Watt Pure Sine Wave Inverter

[maxingout]

I have been searching for a 600 watt pure sine wave inverter for my catamaran. The only thing it will be used for is running a laptop and charging cell phones, sat phone, camera batteries, iPad.

No big loads. Most charging will be done through USB style port.

Probably even a 400 watt inverter would work for me as long as it is pure sine wave. I would rather have a couple of small pure sine wave inverters rather than a large single inverter. That way I will have back up incase an inverter fails.

What inverters should I consider?
What inverters should I avoid?

Thanks