Express and Express 4K Plus work similarly to the Ultra but with fewer high-end features. It’s a streaming box not unlike the devices Roku has been known for since 2008.
Of the two devices, Roku Streaming Stick is the winner. The Express’s lack of Dolby Vision is a major setback And its 4K Plus model is the only version that offers 4K HDR.
No. A Roku TV will do the same as a Roku device, so there’s no need to purchase a new Roku device unless you want to.