I agree with the comments and your question is an interesting one. Let's look at it this way, for the majority of co-ops the debt to income ratio is 25%. That means that only 25% of your income can go to maintenance & mortgage. If your monthly payments exceed 25% then you have to put more $$ down. Don't panic yet, some building will permit buyers to go up to 30% debt to income ratio. I strongly suggest to use the 30% formula and if you still have to put $$ down to meet that and you're in a somewhat secure employment I would go for it. Please, please ask what the closing cost is!!! If you were using a broker as myself we would cover all that for you. You don't want closing cost of new construction to be eating into your down payment. I'm here if I can be of service, and keep the faith!!!

Lately the smalle apartments have been doing better, mortgages are harder to get for units that will have a mortgage above FNMA limits, the action now is in smaller units where rates are lower.
But I agree, do not stretch yourslef too thin, give yourself a buffer

I agree with Gail. The 2 BR rule of thumb doesn't apply to Manhattan. 1 Bedrooms will always sell and rent in Manhattan. Even studios are great investment in Manhattan. A 2 bedroom will rent for more but your costs will be more it's all relative. A brand new luxury building in Harlem will be a good investment regardless of its size.

If you can afford the 100,000 more go for it, but if it is going to put you in a financial bind I wouldn't recommend doing it. Not only is your mortgage going to increase, your condo fees will also be higher.

If it were me, I would NOT want to be house poor; you can always trade up.