I really like the meat and bun on the Shack burger. The salted caramel milkshake is also divine. However, I will likely never order their fries again. We tried the fries "all the way", which are crinkle cut topped with cheese, bacon bits, and red peppers and it was rather underwhelming. Not enough cheese and too much chopped red peppers, and the fries should be crispier.
Of the burger chains I've tried so far, I like Shake Shack's burger more than 5 Guys. It is very different from In n Out, so I really can't say which of those two are better. Can't remember the burgers I've had at Habit Burger, so it might be a combo of: it's been too long since I had Habit Burger and they were too unremarkable to remain in memory.