If you are a ‘try-hard’ or pretty experienced/skilled in FPS-games, then BFV is the game to play. BFV is more tactical, has more skill based gun-play and is more focused on team-play than BF1.
BF1 can become annoying because of the badly balanced infantry vs. “everything else” (elites, behemoths, vehicles and cavalry). Things are much more random and it’s often harder to “control” what happens (high number of random deaths). The higher TTK of BF1 is a matter of taste (really not that high after TTK2). But the polish and ‘immersion’ of BF1 is among the best of any BF-game ever made and much better than BFV.
Both are great games but probably for different audiences.
But BF1 will drive you crazy because of the “casual” and unbalanced gameplay (elites, behemoths, grenade-spam, vehicle-balance).
BFV still has the possibility to become a very great game, if Dice can fix the issues in the game (or rather, do it fast enough). The core game-play is better in BFV, but the immersion/feel will probably never reach BF1.