Fudoh's review in this thread
Bob's review on Youtube
UPDATE - New info from Mike Chi:
mikechi2 wrote:I honestly don't have an official feature list because the firmware keeps evolving due to constant delays in production. Parts have been extremely hard to come by and we've spent months hunting down pieces to finally get the assembly line going. Got nothing to do but twiddle my thumbs and write firmware. So I guess that's good news in a sense, haha.
At this point, I can confirm a motion adaptive deinterlacer, fully compliant CEA-861 style timings (both 60 Hz buffered or frame locked to the console), no loss on resolution change in buffered mode (and sometimes in frame lock too) and a polyphase scaler that can do sharp, non-integer scaling. 1440p is supported via VESA CVT-rb timings but not all TVs take this. 1440p also requires the system to run at 185 MHz, which is beyond the spec of the HDMI chip, although the Cyclone IV achieves timing closure. Hence, the official moniker '5X' and not '6X', since 1440p is not guaranteed. There's also an experimental downscaler that can produce 240p from 480i, 480p and 720p.
Auto-phase selection is available for SNES/TG16 256, PS1 320, NEOGEO 320, N64 320, Saturn 320, Saturn 352 and PS1 384. All you need to do is select the base mode and the FPGA calculates the optimal phase.
Inputs are SHART RGB, SCART Composite video (Pin 21), YPbPr, S-video and composite. SHART RGB and YPbPr supports 480p. YPbPr also supports 720p and 1080i (although those two modes are limited to 422 subsampling, but this device isn't targeted for those use cases). The SHART port might also support 720p and 1080i, but this has not been tested.
No smoothing filter. I could make excuses on how I hated the effect, but implementing that in a custom FPGA design is beyond me atm.
I don't think there's a thread for the upcoming 5x-Pro here yet. It's still in the prototype phase I believe but it looks like it's shaping up to be a great piece of hardware. Voultar's been testing one and sounds rather enthusiastic about it:
Sampling phase seems like it's much easier to get dialled in (automatic?) than the OSSC