Pure sine is still a bit more expensve. but in my view worth it, funny
things happen to some devices on modified sinewave systems.
As to integrated or seperate, its a toss up, in my experience its usually the invertor that goes belly upfirst. Its usually cheaper to go with integrated and less cables
As to brands, well I suggest good quailty units as I have had my fill of cheap
invertors failing, Mastervolt, Victron, Xantrek avoid the cheapy chineese no brand stuff.