I put OpenWRT on an ERPro-8. It worked very well and had more features than the stock firmware. USB modem support was what pushed me to OpenWRT. The storage took a dump in the router (soldered on) so it was fun while it lasted. The MikroTik RB5009UG+S+IN is looking pretty sweet.
I'm running openWRT on my edgerouterX, and so far (about 2 months) everything has been really well supported including hardware offloading of various features.
In most cases, I'm getting better than stock performance. UI is much better too. I'm a big fan.
I didn't know this was an option but I'm definitely going to look into it now. I just bought one of these for my home lab.
Cool. From what I find online, it seems like PoE and SFP (with the X-SFP) are both supported? Any experience with those?