Yes, condos with 421-a offer some big bargains (so 550 Vanderbilt competes well)

"The End of a Giant Tax Break Creates Bargains in New York Condo Market," the Wall Street Journal reported 4/25/18:

Time is running out on one of the biggest benefits in the new condo market in New York City: microscopic property taxes.
Buyers can still acquire glamorous and expensive condominiums and pay almost no property taxes for up to two decades or more in a dwindling number of new developments--but the deals are disappearing

After all, last year, the state legislature eliminated the tax break almost completely, thus jeopardizing new Atlantic Yards/Pacific Park buildings. The article notes:

Technically the abatement is still available in small, less expensive buildings outside Manhattan for buyers who make the condo their primary residence. But Paul Korngold, a lawyer who specializes in property taxes, said the regulations are so strict that few if any buildings will qualify.

Unmentioned: that includes 550 Vanderbilt at Atlantic Yards/Pacific Park, where, as I wrote for City Limits last year, that very same Korngold managed to help buyers get a huge discount on taxes by pairing that condo building with an affordable building down the block.

This year, that tax break is ever more valuable, given--as the Wall Street Journal noted--new federal rules limiting deductibility of state and local taxes to $10,000 a year.

An interesting quote from Andrew Barrocas at the brokerage MNS, who cited the pressures on the condo market in Brooklyn: "Investors are not really interested in a building without an abatement. It doesn't make sense for them."