Get a Victron Multiplus 12/3000/120 with remote. Full sine wave from
inverter. Brilliant piece of kit and will operate as a UPS, an
inverter to parallel with mains supply if on low shore current. Fully
configurable by software on a PC and network cable. Can parallel
units for more AC/charging or even put 3 together to make 3 phase!
Probably pricey, but cheaper than Mastervolt and far better/more
reliable that cheap individual units from Taiwan.

http://www.victronenergy.com/upload/...1000-D-bUS.pdf