OTP
Cons
Taking gamble on realestate and interest rate market at time of settlement
Can't be 100% certain of the product you are buying until you see it built
Competition for tenants at time of settlement
Worse cash scenario is that the product is disappointing, values drop and cost of finance increases by setlement. You have to put in extra funds to make financing possible.
You should look at each risk and assess it on merit.
Con 1. RE prices and interest rate will hit you even if you buy estabished, unless you do this and lock the rate in. If it affects your serviceability, confirm that you can still service it if rates go up.
Also, you may need a buffer if vals on completion dont go right, but dont you get the loan approved when construction starts?
Con 2. You can look at the developer's previously built homes, display homes etc. Should give you some comfort.
Con 3. If you buy established, and a tenant leaves in 12 months time, you'll be in the same boat from a competition for a tenant perspective anyway.
Worst case scenario is a combination of all 3. If you believe in the area, and can cover the risks, then they dont appear as scary.