You can call me anything you want!
For now. I main mostly Strike Freedom and Brave commander in Maxi Boost. I main Rx78 in Full Boost with SF, Freedom, Noir and dynames.
I don't know what was my mains when i started out. Since i started during the Zeta DX period. I pretty much know everything about the system when EXVS was released on PS3. The cloest answer would be Strike Freedom as 3K IJ as 2.5K and RX78 as 2K.
I say its best to play some simple suits like RX78 first. Try to build up your skills.. then move to some more complicated MS.
As for newbie friendly> Rx78 for 2K. Noir/Freedom/IJ for 2.5K Xi Gundam and Unicorn for 3K
When you think that you are good enough for some more complicated MS. You can go reborns or wing zero *TV* (The most OP suit out there with 2500 Banshee)
Those 3 are the strongest suit in FB EXVS
Hope my answer helps!