F34 Questions

Okay, I get that the aesthetics of the F34 are... divisive (to say the least!) but... honestly, it feels like the "right" interior arrangement for my family. That said, would r/BMW care to comment on any mechanical or design drawback (OTHER than "the look") that I should know about before purchasing a new F34, likely a 340i? Once I'm behind the wheel where aesthetics don't really matter, am I getting the "full BMW" feeling? Are the critical options to include? (Level set: this is a trade-up from a 140hp VW TDi, so, even a F34 330i with NO optional equipment is going to feel like a rocket ship...).

Bonus points for explaining the 4-series Gran Coupe and how it compares to the 3 GT... I'm a little confused by the even-numbered series as it is, since the engines are the same as their minus-1-odd-number counterparts, so Is it just "marketing," or is there a substantive difference in the drive between, say, a 3 and a 4...?