[Q] v50020 a/b/d differences

[cerps]

I'm rooted and on stock 4.2. I'd like to upgrade to 4.4. I'm trying to understand the difference between the different a, b, and d versions of v50020 so I can chose which one to flash. My searches didn't really find me a comparison. I think Gamma is better on some than others. Can anyone point me to a comparison so I can make a decision? I don't want to just OTA because I'd like to keep the same Aboot so I maintain the Loki exploit.