@makaiguy wrote: What input connections are available on the tv you intend to use the Roku with?
HDMI of course.
Well, not "of course", really. The Roku 2 XD had both HDMI and composite outputs so you could be connecting to an old tv that only had composite inputs via a special cable. That's why I asked.
All current models have HDMI ports.
The Express and Express+ support resolutions up to 1080p. All other models support up to 2160p (4K) but can be used with non-4K sets.
Express supports infrared (IR) direct line of sight remote only. All other non-stick models, including Express + come with and use wifi direct connect remotes that don't require line of sight, but support IR remotes as well. Stick models are typically used behind tv's where IR can't reach and support only wifi direct remotes.
Express and Premier models have only single band wifi capability, so they can connect to 2.4 GHz wifi only. All other models have dual band wifi and can use both 2.4 GHz and 5 GHz wifi bands.
If you want to connect via Ethernet rather than wifi, the Ultra is your only choice.