with more plants you dont really need a veg room and have much quicker turnover but you can get in trouble a little more with the Law ...
with less plants, it takes longer(unless you have a separate veg room) but smaller plants are easier to manage and care for...
I kept going back and forth between the 2, now I have found that what works for me is a happy balance, some small plants and some bigger, I like variety too much to grow only 2 massive trees
as Lord Mega said, scrog can be annoying when you want to move things around or inspect the plants, my plants are usually sturdy enough to hold themselves