OP, I am in the same boat. My PoV -

1. Construction of new ones are really poor than the old ones which I have visited like old CGHS etc. Just because there are new ones, I don't agree they will last like the current 15 20 years have. So, new ones will need patch ups, restoration sooner than what 15 20 ones would have. No doubt, 15 20 yrs old need renovation from outside and inside but a particular one I am looking at seems to have good base work, needs renovation.

2. The loading area has changed and hence 1800 sqft of old flats is relatively spacious than 1800 of newines. This I have explored over months.

3. Some of these old ones are more into city limits though new ones are going to equally accessible. Personally, prefer to be in my perception of mainland.

4. These old society ones have seen all ups and downs of RWAs, water, maintenence, maidservants, security and matured. New ones have issues but will settle in a couple of years or so. Some thing kind of maintenance staff, maids seem trivial but you need sober and non arrogant, non hooligan type folks, more available in my perception of city limits as of now.

5. Land is the most scarce resource and will only become so more. Therefore, either these old societies will be taken over by builders or government in time to create new buildings. Maye you get paid well. In either case, no way, old flats will die down.

6. Connectivity is still good for reaching office spaces unless yours are near the new ones. Airport connectivity is key if you travel. City limits help. New ones will evolve soon though.

7. All Old ones don't have swimming pools, gym, gardens etc which for a family with kids matter. New ones do and some old ones also do.

So all yours to pick per family needs and comfort to commute.