I have the Roku Ultra, uh, the cheaper one (they appeared to have identical specs and ports) which is a nice slim box, best remote in the industry (although the addition of those shortcut buttons was unwise imho), and use that on the older flatscreen (40” Phillips, 4 HDMI ports, times have changed). I’ve got a 50” Roku TV in the bedroom, and the interface on that is quite similar to the box, and quite acceptable.
The 55” Roku (I’m not sure of the brand) has a terrible interface, incomprehensible menu system, and I plan to give the thing away to someone I know if they agree to help me with some stuff around here. There’s nothing wrong with it, other than, who the you-know-where thought this software makes any sense at all.
Oh, and I need to stop buying TVs.
The Ultra appears to be in just one model, and the lower price. Annnnnd, it still has the RJ-45 port.
https://www.roku.com/products/players
Just buy a 25 dollar roku stick for the 55..