I bought a Steam Link a while back, and while I don't use it terribly often, it's a purchase I've been quite happy with: It's easy to set up and use, and streams games from my PC to my TV smoothly and reliably. I even bought it at 50% off, which means the only times I'm unhappy with it is when I see it on sale for 90% off. So, I wasn't especially thrilled when I learned last week that Valve is releasing a Steam Link app that sounded like it could make my physical Steam Link box completely obsolete. The free app for Android and iOS lets you stream games to connected devices like phones, tablets, and TVs.
After a few days of trying out the Steam Link app for iOS (I don't own an Android), I can say pretty confidently that it doesn't make my Steam Link box destined for the scrap heap. The app works, and often quite well, but it's not as smooth or reliable an experience as the actual Steam Link box has been.
I started by streaming games to my television using an Apple TV box (note: I did not own an Apple TV box, but Valve provided on to me for testing purposes). With the Steam Link app installed on the Apple TV, it detected my PC running Steam (while using a wired Ethernet connection) in the other room, then gave me a code to enter into that PC. From there, I paired a Bluetooth-enabled Steam controller Valve also sent over to the Apple TV, and was ready to roll.
At that point, it works the same as my physical Steam Link does. I can view my library of Steam games on my TV in Big Picture mode and begin playing. One thing I noticed when beginning to stream a game using the app is that there's generally a period of about four or five seconds where the stream really crawls and stutters before recovering. A couple of times while trying to stream a game, I would only get a black screen when launching from my TV. Usually the game eventually loaded after a short wait, but two or three times I had to get up and walk to my PC in the next room and relaunch it from Steam's Big Picture mode. I don't recall ever having an issue launching a game with my Steam Link box.
I played a few games on my TV: Rocket League, Cuphead, Super Mega Baseball, and What Became of Edith Finch. Usually, once the game was streaming, even if there was a delay in launching it, the performance was smooth except for an occasional dropped frame or stutter here and there.
There are settings in the app for streaming quality: you can choose from Fast, Balanced, or Beautiful (I swapped between Balanced and Beautiful a few times, without noticing any change in visual or performance quality), you can set bandwidth limits from 3 MBit/s to unlimited, and you can limit the resolution, if native res is too taxing for your connection. A network testing option will tell you if your system will be able to handle running the Steam Link or if you'll need to make some adjustments in the options menu.
Playing Rocket League online on my TV, I had occasional dropped frames or stutters now and then, though it's hard to say where the problem lies—with my connection, with the Steam beta I had to opt into for these tests, with the app itself, or the Apple TV box. These little skips didn't make the game unplayable, but it's neither as smooth as it is on my PC or on the Steam Link. I can imagine it would be frustrating in a competitive match.
I unplugged my Ethernet cable and tried the same games over my 5GHz wi-fi connection, and not unexpectedly the performance wasn't quite as smooth, though everything I tried was still highly playable.
I had issues pairing my Steam controller with the Apple TV box a number of times this week. Usually it spotted the controller right away, but occasionally it took several tries, and once or twice after it had detected the controller, I'd answer the prompt to pair the controller only to find it hadn't paired. So I'd have to try again, sometimes repeatedly. With my physical Steam Link box, I don't recall ever having issues pairing a wireless controller to it. Again, it's hard to say if this issue has to do with the app, the Apple TV box, or the controller itself, but something still needs some work.
Since I don't own a tablet, it's a little hard for me to imagine wanting to play a PC game on my phone using a Steam controller, but I did give it a shot and it works really well. I tried the same list of games I used while streaming to my TV. I was able to use the iPhone's touchscreen a bit, too—swiping a finger around is like moving your mouse, and poking something you can click with a mouse pointer, like menu options, also works. Though using my iPhone's small screen for PC games felt weird, I can easily imagine the app being a nice option for playing a PC game on a tablet with a controller while lying in a recliner or on a couch.
Despite the new options, I am going to hang onto my physical Steam Link. It's more reliable, I don't have issues launching games or pairing controllers, and streaming to my TV is ultimately smoother than it us using the app with the Apple TV box, at least for now. At any rate, the app is free, so I can't think of any reason not to give it a spin, even if you already own a Steam Link box.
It's now available in beta for Android phones and devices, though it's currently awaiting for approval from Apple before iOS users get to try.