I like FLATBUSH due to it’s lovely convieniences and variety of yeshivos. Flatbush is home to great yeshivos and yeshivos that have great limudei kodesh and limudei chol. My Brother lives in lakewood and he is yeshivish so he fits in there. As you mentioned it is hard to get your children into yeshivos if you arent in kollel. Also, there are Very very few yeshivos in lakewood that have a good limudei kodesh AND limudei chol. Also in highschool most yeshivos don’t even have limudei chol and the ones that do aren’t considered top yeshivos.
On the other hand, in flatbush, there are yeshivos with good limudei kodesh and chol. and in the MARINE PARK area of flatbush there are many many young couples moving there because housing is a bit cheaper there.
And Btw, where in manhattan do you live?