The RBK30 (left, above) and RBK40 (middle, above) retain the dual-band 2x2 AC1200 class device-connect radio but change the dedicated 5 GHz backhaul radio from 4x4 to 2x2. NETGEAR has assigned the AC2200 classification to both products, the same as Linksys' Velop, introduced at CES 2017.
The RBK40 retains the desktop router / satellite architecture of the original RBK50 Orbi, including four-port Gigabit Ethernet switches on both. The RBK30's wall-plugged (but not HomePlug enabled) satellite has no Ethernet ports.
All Orbi models operate without an associated cloud service, unlike many other distributed / mesh wireless systems like eero, Luma and Google Home. Also unlike many of its competitors, Orbi supports features such as IPv6, dynamic DNS, a full range of port forwarding options and OpenVPN.
MSRPs are $299.99, $349.99 and $399.99 for the RBK30, RBK40 and RBK50, respectively. Satellites for each SKU are also available for $149.99, $199.99 and $249.99. Everything is shipping now.