There's only one that would be considered equivalent, and that would be the Ultra. It's the only one with an Ethernet jack and a USB port. The latest Ultra, that will be available tomorrow, updates the USB port to 3.0, but removes the SD card slot. Personally, I've never used the SD card in any of my players. The new Ultra also adds Dolby Vision and AC-4 audio support. If DV isn't important to you, the currently available version (model 4670) might be on sale from some locations since the new one is coming.
Dan Roku Stick (3600), Ultra (4640), Ultra (4670), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.