The Acer XB280HK is a 28" 60Hz 4K G-Sync TN, and will be available sometime in October. Unless another company unexpectedly beats them to the market, this will be the first 4K G-Sync monitor available.
The MSRP is $800, which makes it an interesting competitor to the 27" 144Hz 1440p G-Sync TN Asus PG287Q, which also sells for $800. Will you miss the the higher Hz if you have more than twice as many pixels and still have G-Sync?
http://us.acer.com/ac/en/US/press/2014/82208
http://www.pcper.com/reviews/Displays/Acer-XB280HK-28-4K-G-Sync-Monitor-Review
http://hothardware.com/Reviews/Acer-XB280HK-4K-GSYNC-Gaming-Monitor-Review/
The MSRP is $800, which makes it an interesting competitor to the 27" 144Hz 1440p G-Sync TN Asus PG287Q, which also sells for $800. Will you miss the the higher Hz if you have more than twice as many pixels and still have G-Sync?
http://us.acer.com/ac/en/US/press/2014/82208
http://www.pcper.com/reviews/Displays/Acer-XB280HK-28-4K-G-Sync-Monitor-Review
http://hothardware.com/Reviews/Acer-XB280HK-4K-GSYNC-Gaming-Monitor-Review/