In addition to the great responses so far, let me add a few things.
Builders are not known for reducing the sale prices and may suggest they’ll throw in some upgrades if you don’t use your own representation, however, a good buyer rep will still negotiate those things for you AND get you a possible price reduction.
Your rep will point out differences in the builder’s sale contract (as they don’t typically use the State Real Estate agreement, at least in my experience). These differences include the appraisal contingency, which requires the buyer to cover any difference if the appraisal comes in low, unlike the State contract which allows the buyer to negotiate the price, or terminate and get earnest money back.
I was recently able to negotiate a substantial price reduction for my buyers after a low appraisal on a new build.
A buyer rep may need to be a squeaky wheel to get various documents or State electrical inspections or the certificate of occupancy if the listing side is dragging their heels on deadlines.
I have had to be persistent with the sellers rep to get these things done in time on a build that was falling behind the timeline and the buyers rate lock was about to expire, meaning they would’ve had to nearly double their interest rate!
Of note, many builders are offering discounts or credits where I am since the market has cooled and buyers can benefit from interest rate buydowns. If you don’t have an agent, you may not be aware of the savings offered, so definitely ask.
If the building is not yet complete, your agent should and could ensure that you get inside for a few walk-throughs to check on progress along the way.
Lastly, if you are looking for a new build and a completely new neighborhood, just remember there might be an HOA which could limit the number of rentals now or in the future.