If you have a big enough converter then there are some serious advantages to using a true sine wave inverter (or two) to power selected electroincs in your RV. True sine wave inverters put out clean, consistant power. if you overload them instead of "Browning out" like the power mains do they simply shut down and get annoying (BEEP BEEP BEEP) spikes, surges, brownouts, and such that bother the blazes out of delicate electronincs, TV's and such. Well getting those past a good quality 3 stage converter, A few hundred amp hours of battery and an Inverter.. Simply not going to happen.. A direct hit from lightening.. That might make it.. (But I've seen such a system stop even one of those).
(That was one very well built system).
That is all I'm going to say save this:
There are many good True Sine Wave inverters out there.. Alas, I can not recommend any one of them over the rest. Sorry.