TTN doesn't even fully support class-A yet
as far as I know the following is still missing:
- no confirmed sending (yet) meaning that the node gets an acknowledgement from the gateway the packet successfully arrived.
- no dynamic over the air pairing of nodes (yet), only static (activation by personalization)
- no sending back data to the node, in class-A each end-device's uplink transmission is followed by two short downlink receive windows, in which the "network" can send back data to the node, this is not supported yet.
anyway... you can buy any gateway you like, even the D.I.Y. ones, because they all use semtech SX1301 boards .. it's just a matter of updating firmware to get new functionality, so all g/w hardware is OK