PokerStars - 4000/8000 Ante 800 NL - Holdem - 7 players
Hand converted by PokerTracker 4

UTG+1: 98,489 (VPIP: 24.00, PFR: 17.57, 3Bet Preflop: 0.00, Hands: 75)
MP: 169,700 (VPIP: 19.43, PFR: 13.62, 3Bet Preflop: 8.55, Hands: 315)
CO: 114,383 (VPIP: 14.24, PFR: 12.64, 3Bet Preflop: 6.52, Hands: 6,632)
BTN: 119,708 (VPIP: 13.70, PFR: 11.59, 3Bet Preflop: 3.70, Hands: 74)
Hero (SB): 151,024
BB: 63,892 (VPIP: 17.44, PFR: 14.90, 3Bet Preflop: 6.96, Hands: 4,393)
UTG: 98,304 (VPIP: 20.51, PFR: 13.16, 3Bet Preflop: 0.00, Hands: 39)

7 players post ante of 800, Hero posts SB 4,000, BB posts BB 8,000

Pre Flop: (pot: 17,600) Hero has J A

fold, fold, MP raises to 16,400, fold, fold, Hero ???

Shove, fold or flat?

His attempt to steal that session was 12 over 50 hands or so

First of all, 315 is not a sample size to judge his steal attempts IMO. Secondly, 19/14 is not that tight in 180s, especially if he is mass multitabling. If he's a reg or decent player, he will recognize this situation as a good steal spot. He's commited only vs sb. I would shove and be really happy about it. I also think that, some players will have r/f r/c and shoving range in this scenario. Given the fact that it's a good steal spot + he has a huge stack + you put a lot of pressure it's a clear shove to me.

So flatting is the worst, with shoving the best?

i would think so

Shoving is standard, flatting is less standard but very viable, our hand flops rly well