Im replacing mine shortly also, so far my very limited research has me heading toward Mongoose with 9" screens, not cheap, but pretty decent quality...I have 7" screens at present, 1 of which stopped working recently...
If you've had them before then you would be aware they cop and flogging when your 4wdriving, I don't ever use them in this situation, but the bouncing and rough stuff surely wouldn't be doing them much good.
When mine were first fitted they didn't sit to well on the sleaves on the seat, so I fiddled a bit and also locktighted the screw in sections to help reduce it coming undone etc..
Cheers..