I've got the previous generation Roku Stick hooked up to a TV, and Netflix is painfully slow to load and navigate. Where you may run into trouble is with Netflix. The loading screens may take just a little longer than I'd like, but we're talking a matter of seconds. I'm running Plex on an old Roku 2 which didn't have a great processor, and Plex works fine. The Roku Express should be fine for Plex.
