Help a returning player please?

So, I'm probably like many returning after the massive patch update and lost. But my problem lies in the fact I'm not sure what do do with my mech "pool".

I have a JM6-FB, a JM6-DD, a JM6-S

Do I sell two of these variants? It seems with this new leveling system you no longer need to have three copies of the mech.

And if so, which one do I sell? Is there an ideal Jager at this point, or has it been nerfed to oblivion?