Why hasn't Roku come out with a device that you can hard wire to your internet. I have 5 tv's and 5 Roku's. I have periodic issues with connection which means every day. If I could hard wire the device it would eliminate the problem.
The Ultra has an ethernet port, most of the TVs do also. Of my 5 TCL TVs only 1 (cheapest 32") doesn't have ethernet.
That said, 3 of those 5 TVs and a stick in my garage are all on Wifi and I haven't had any issues. Wifi is extremely reliant on environment and equipment.