Well the RAT7. its simply a rather inexperienced manufacturer, which might have great innovations but many of those have had it and finally failed at a certain spot, its usualy endurance. They can look as stable as they wish, its not failproof***. But for those who want to risk it, it surely is a fun new toy. It got endless adjustable stuff but that makes it aswell just pretty heavy and for some people in some way to complicated or unpleasant to use. Its simply "love it or hate it".
So ultimately only those 3 could be "good to go" in my view:
MX518: Best price/power ratio + highest endurance but lesser functions
G9: Is in the middle spot and got the advantage of both, but doesnt exceed at anything
RAT: Is the most adjustable but it may lack reliability and isnt easy to maintain, aswell a bit heavy (need some skill and its truly love it or hate it)