Been looking at the two Battlefield games I have right now - 1 and Hardline - and I want to post my thoughts.
First, let's go with 1. Frankly, I'm enjoying it so far, as a casual; found that I am pretty fond of SMGs, mostly, though I've been giving a few looks at the other classes as well. Progress is slow, but that's okay; I'm (mostly) enjoying the time I'm having with the game, learning the ropes and getting slowly better at points. Victories are few and far between, but I'm making progress. The fact that the game itself still seems to be fairly active - there's a pretty good variety of servers available - is also good, as it helps me learn to be a bit better. I will admit, it does get frustrating getting destroyed by sweats in some games; I've had a few points where I'd get absolutely stone-walled by some high-level player with really strong equipment, and there would be nothing I could do about it. Still, At the very least, I feel like I'm getting better.
By contrast, I'm struggling to enjoy Hardline these days; can't really play any of the classes all that well, and the only server I've been able to consistently play is a Conquest game on Downtown. Learning the different classes is, frankly, frustrating; I have difficulty getting kills with just about anything, with my current best gun being, ironically, the starting MP5K for the Mechanic class. Even then, I still get outgunned by just about everything, with my only real success being trying to flank and ambush lone players. Even then, my connection is shit; more than a few times, I light up someone, he takes no damage, then turns around and kills me in what felt like one shot. Doesn't help that the sole server I got is badly unbalanced; it's usually completely one-sided, with one team getting constant helicopters and armored vehicles, and pretty much always controls the points, with the other team being unable to do anything.
TL;DR, having fun with 1, but Hardline is testing my patience.