Hard to say, OP. Really depends on which multiplayer formula you prefer.
If you like Call of Duty's fast-paced formula and find that you can pick up and play that style more, I'd say Titanfall 2. However, if you're playing with friends and there's at least 3-4 of you and you'll be able to play together a lot of times, then maybe BF1.
But if you think you'll still play even when they're not around a lot, then maybe TF2? Battlefield (not BF1) is just super annoying when playing with randoms. You'll literally question how some of them are able to turn on their PCs/consoles much less play well.
I played both betas extensively (reached level 43 in BF1 beta, and unlocked everything in TF2 test), and I'm going for both. Each game should be a good break from each other. If I'm in the mood for fast paced gameplay, then it'll be TF2; but if i want that military FPS feel, then BF1. I'm a big BF fan, so there's no way I won't play BF1 even if I hate some of the design decisions and such.
Kinda off tangent here, but if you've played the two, you'd understand where EA is coming from why they\re releasing so close to each other. EA is playing it safe so that if shootbro joe doesn't like WW1 weapons and such, they have TF2 to play instead of Call of Duty. If they don't like CoD and/or TF2, they have BF1. And then there's people like me who'll play all of 'em and stick to what I like the most.
Not saying it's right since their idea could bomb and cannibalize each games' player base, but maybe they crunched some data and found it the best solution rather than waiting a year.
Anyway, OP. if you can, play both and what clicks to you the most, that's what you'll recommend to your friends.
EDIT: Also, OP, seeing as you're familiar with Battlefield, then you know that BF1 will most likely have lots of bugs and be ironed out maybe a month after release or something. This is how Battlefield games have been and I don't see it changing anytime soon. I mean, I don't know the build the beta was based on, but there were a TON of bugs. Bugs you can live with and will no doubt be patched, but they were there.
Titanfall 2 though, felt polished and honestly, felt like it could be released this month.
Not sure if you care, but we did pit the two betas (tests) against each other:
http://www.playstationlifestyle.net...nfall-2-vs-battlefield-1-battle-of-the-betas/ And yeah, I know it's kinda pointless a bit since we don't know everything about both games (modes, maps, weapons, progression system, etc) but it might help.