Should I be eating 1200 or 1500 calories?

If your TDEE is really 2,000 and you eat 1500, you'll lose about a pound per week if you are logging/weighing your food accurately. You'll lose a little more than that if you eat 1200. It's a personal decision. I think eating 1200 stinks.

The goal shouldn't be to eat the littlest you can and still survive. 1500 even sounds a little low. If you take 20% off your TDEE you can eat 1600 and still lose a good amount of weight. You want to be sure you're providing your body with adequate nutrition and losing in a healthy way, or at least I would want that, rather than just providing your body the bare minimum to keep you alive.

I've done 1200 in the past, and I was hungry all the time. I couldn't wait to get to my goal and go back to not being hungry. I didn't have long-term success.

This time around I'm eating 1400-1500 and I'm watching my macros to make sure I'm getting a good mix of nutrients. I'm not hungry and I don't have a specific goal because I'm comfortable with this and I feel like I can keep doing it. When I reach a weight that works for me, I'll just add on enough calories to maintain rather than lose weight.

It's a personal choice. You could do 1200 (if it works for you) and there's no reason to think you'd have a harder time keeping it off, but then you also could lose at a slower rate if that's more pleasant.

1200 is probably close to 2 lb/week; 1500 would be less (but it's more important to add back even milder exercise with 1200, so depending on how it's implemented it might not make much of a difference).

The key thing is how to do you feel on lower calories, are you happy and satisfied, do you feel restricted. If you do lower calories and end up bingeing or going way over a time or two a week, you'd be better off on higher calories. But some find it helpful when they have lots to lose to lose faster. I did 1250 and lost fast at first and for me that allowed me to get back to exercising more vigorously more quickly which was motivating and ultimately allowed me to raise my calories, and I felt good on the lower calories then (and couldn't do 1200 now, I'd hate it).

So don't worry about what other people did or say and figure out what works for you. There's a whole range of calorie levels you can lose on. But to lose over 70 lbs you need to find something you will be happy on long term (and same for not regaining).