What to look for in an inverter/charger?

I run a Xantrex Freedom SW 3012. I have the main power cable go to the generators transfer switch, then a subpanel with the AC's, converter, and Electric side of the water heater. There is a pair of 30 amp brakers going to the I/C. The I/c powers the factory panel with everything else on it. 3kw running 6kw surge 150 amp charger. With the wired remote you can program it with the incoming power braker, and the charger will power share with downstream loads - turn down the charger when you are making coffee, thru it back up when you are done - automatically.
I have a 100 amp converter on the sub panel for those times when I only have 20 amp service, and need to do double conversion to keep the coffee pot, toaster, microwave, and/or hair drier happy at the same time.