If AMD can ship a card in June that costs under $200 and compete with a GTX 970~980, simply wow! Plus packed with the already out there open-source Linux driver support. This Polaris 10 card won't be able to compete with NVIDIA's new GTX 1070/1080 "Pascal" cards (AMD's higher-end offerings will come out later this year with "Vega"), but for delivering performance-per-dollar this could be quite an attractive offering if these initial reports are true. Plus there's the open-source AMDGPU Polaris support compared to no open-source driver support yet for Pascal. NVIDIA did supply a GTX 1080 card to Nouveau's lead developer, Ben Skeggs, but it still could be months before NVIDIA releases the necessary signed firmware images for allowing accelerated hardware support.
Other leaked details say the Radeon RX 480 will have 8GB of GDDR5 memory, up to 5.5 TFLOPS of compute power, 256-bit memory interface, full HEVC support, DisplayPort 1.4 support, async compute supported, and other Polaris 10 details that have already been speculated. The $199 alleged pricing was revealed by the WSJ a short time ago.
Stay tuned and I'll certainly be watching the AMD Computex live-stream.
UPDATE: The $199 price confirmed, more details here.