Buying a property from the builder is a good thing. You are buying a NEW HOUSE, with probably
10 year warranty. Also, pre construction homes you may get a discount on the price. Advantages its YOUR new home, and no one has lived there and left their troubles It is a clean slate. Your no closing cost is almost correct, you will need to pay taxes and insurance. Your mortgage will be slightly higher but not much as rates are in the low 4%. You have some money to buy your new furniture to go along with your new house.
When buying, your mortgage payment has to be comfortable becuase if its not then this kind purchase is not for you.
Disadvantages: After 1 year your taxes will adjust,will most likely increase.