The new Roku devices can be grouped into three basic categories: the beginner devices, the high-end devices, and the stick.
The one that impressed us the most is actually the beginner devices: Roku Express and Roku Express+
Roku Express/Express+They are basically the same device, except the Roku Express+ includes the ability to connect to an older TV using the composite connection (RCA-type plugs). The devices use the line-of-sight IR remote, but can be controlled by the Roku Mobile app that's available for Android and iOS. It's also great for travel, if you wish to use your Roku on the go. For that purpose, though, the Roku Express+ would be a better option than a Roku Express, because of the additional composite output. I've been surprised at the number of hotels that still don't allow users to connect HDMI devices to a TV.
The $29 Roku Express (model 3700) is a very responsive little device. This is true of the $39 Roku Express+ (model 3710) as well, since they are practically the same device.
The devices work as well as the previous model Roku 2/3 devices. The Roku Express and Roku Express+ don't have all the features, such as Ethernet port, USB port, or microSD card slot, but they are quick little devices.
They are great for someone beginning to stream, for travel devices, and for secondary televisions. In fact, they are perfectly acceptable as primary streaming devices.
Roku Streaming StickThe Roku Streaming Stick (model 3600) was actually introduced in April 2016, and was a much-needed upgrade to that line.
One of the nicest features of the Roku Streaming Stick is the fact that it plugs in behind the TV, and there is no box or wires visible. This is particularly nice for wall-mounted sets where cords and attached devices can ruin the aesthetics.
At $49, it's a good choice for a streaming device.
Roku Premiere/Premiere+/UltraThe newest and fastest Roku devices are the ones that actually failed to impress. There are a lot of good things about them, but nothing that would make us run out and upgrade from a Roku 3.
The devices do sport a four-core processor, which makes these devices the fastest Roku devices ever. However, we experienced lockups when using live-streaming services (in our instances, we were using DirecTV Now and Sling TV). We didn't experience lockups using standard streaming apps, so this may be a problem with the services, not the boxes, but we didn't experience the lockups on other devices (we used an Apple TV to compare DirecTV Now and Sling TV to Roku).
Some users had experiences serious issues with the Roku 4, which is the predecessor to these new devices. The lockups on the live streaming services are, so far, the only issues we've encountered. However, they are a cause of concern.
Despite that, we are generally happy with the top-end Roku devices. We aren't happy with the variations in features, particularly the loss of features on the sub-$100 devices. They do, however, support Ultra HD (4K) video.
The third-generation Roku 2 and Roku 3 devices each had an Ethernet port, a microSD card slots, and a USB port. Those are now missing from the Roku Premiere and are only available on the Roku Premiere+ (except for the USB port) or the Roku Ultra. The Roku Ultra also has an optical audio output port, as did the fourth-generation Roku 4.
The Roku Premiere is $79, and comes with an IR remote. The Roku Premiere+ is $99 and comes with a WiFi Direct remote, an Ethernet port, and a microSD slot. The Roku Ultra is $129 and adds a USB port and an optical audio output.