TLDR: I would recommend BF4 for more hardcore players, but for a more populated and casual experience BF1 will do.
Pros:
Cons:
Conclusion: Buy it, you'll have a great time. Buy BF4 if you want to really stick with a game.
Pros:
- Great atmosphere. Best immersiveness and atmosphere of any game (tied with RDR2)
- Good campaign that really brings you into the war
- Satisfying, clean gunplay
- Excellent weapon balancing
- Elite kits
- Behemoths are awesome, really put up the levolutions from BF4
- Insanely populated, tons of servers available
- Vehicle gameplay is some of the best in the series
Cons:
- Can be overly campy with the artillery truck and one shot snipers
- It's a shame custom servers are now gone
- Campaign isn't that long, but it's not the focus so it isn't really a big deal
- Questionable progression with shortcut kits
Conclusion: Buy it, you'll have a great time. Buy BF4 if you want to really stick with a game.