My opinion is Rebug because it's the easiest one to spoof the newest FW.
You can switch easily between CEX & DEX what is a big point.
3.55 CFW are older one's that have lesser options then the newer ones.
But the 3.55 CFW like KMEAW is stable. Spoofs for 3.55 CFW's are taking more time to release.
If there's a stable one 4.40 CFW it would be the best, but wait a little bit cause it will always getting better.
Hope I can help. Sorry for my bad English