I have one.
I got it a week ago. I needed 4-ports at 2.5G with the 5th port to connect to the 1G network. It works great.
I have not had the time to thoroughly test it, indeed I have only tested it between 2 of my 4 machines connected at 2.5G, and it hits full speed and stays there solid (albeit not for long (drives/arrays being my issue). 🆒
As for cables (
nofanneeded asked), I was previously using direct-connect between 2 individual PC's (no switch) so I pre-bought CAT.7 and CAT.8 cables which work perfectly.
The only issues I have had is that
(1.) RealTek (LAN controller chip manufacturer) no longer allows you to simply download a driver (like they have for a very long time), jump through hoops or download elsewhere (be careful).!
(2.) You need to manually change a couple of settings on the NIC (within W10 at least), Network Connections > Properties > Configure > Advanced > Jumbo Frame [Set this to 9KB MTU]. Also in the "Advanced" section you may need to set "Speed and duplex" to "2.5Gbps Full Duplex" (shouldn't be needed, but if the detected speed drops to 1G and you know that the cables are good you may need this).
(3.) In W10 (at least) you may need to change the "priority" of NIC usage, this article shows how >
https://www.windowscentral.com/how-change-priority-order-network-adapters-windows-10
This IS fanless, this was one of my criteria and why I rejected everything before it. it has 2 sides closed and 2 sides well ventilated, you can see the large aluminium finned heatsink inside. As for heat, I can not comment as I have only tested between 2-machines simultaneously and it is sat horizontally in free air on top of a 1G switch and this is not where it will stay.
I would so far give this a score of 9/10 with it losing a point for minor things, such as all of the "blinkenlights" being on the same side as the ports so depending on placement you may never see them (do you care).! It has wall a mounting option (slot-screws on the back) so if you wall mount, the lights and cables will be upward.
This is a much needed product in the marketplace, and IMHO the beginning of the 2.5G era as a reality.