But if I try to really walk and explore, it's not so great. PlayStation VR, Oculus Rift ( $694 at Amazon), HTC Vive ( $500 at Walmart) and Microsoft VR headsets cast a wider freedom of motion that's still not huge, but is a larger cage to live in.
The other drawback is the included controller. It's the same point-and-click, three-degree-of-freedom motion controller that comes with Google's step-down Daydream View, and while it's fine for basic interactions, has a clickable trackpad and volume controls, and can even be used to do things like cast fishing rods and "grab" objects, it lacks more advanced spatial tracking to match what the headset can do (6DOF, meaning actually accurately tracking the controllers in 3D space with the cameras).
The Oculus Go has a similar type of controller, but since I can't move around with Go, I found the simple point-and-click design fit better. With Mirage Solo, the simple controls ended up feeling limited, and even drifting a bit in tracking (pressing a button on the controller re-centers it, but it's annoying).
I'd love to see this headset get a wider range of motion, and also let me use two controllers with more accuracy and manipulation, like the Oculus Touch's controllers. But that future isn't here yet.
Comfortable to wear for a while, but not very portable
The visor-based way of wearing the Mirage Solo means it didn't press in on my face, and spending half an hour in the fantastic and weird game/app Virtual Virtual Reality was easy. A knob tightens the fit of the visor in the back, and a button underneath the headset makes it slide closer or farther from your face.
But the visor is fixed to the headset, making the whole thing cumbersome and hard to carry in a bag. Maybe you don't envision going on trips with your VR rig, but the Oculus Go is far more compact with its Velcro straps.
The Mirage Solo requires headphones for audio: Lenovo includes a short-corded pair that are fine. But there isn't any onboard speaker. The Oculus Go has a great set of onboard speakers that make sharing VR a lot easier at home, no headphones necessary.
Extra perks: Google's world of VR apps, YouTube and VR180
The headset has some extras that are helpful: a microSD card slot allows expandable storage, unlike the Oculus Go. The headset and controller charge via USB-C (one AC adapter included), which I now prefer to Micro-USB.
Google's own selection of VR apps is really well done: YouTube is a massive repository of videos, Arts and Culture offers plenty of art exhibits to explore, Street View is a fun way to dive into checking out the world in VR and the newof 180-degree 3D videos will work on the Mirage Solo. Lenovo is making a separate $300 Mirage Camera that shoots these 3D photos and videos. That's not a reason to pick Google as your VR ecosystem, but it shows progress.
Tomorrow's VR, a bit too soon
VR looks like it's all the same, but it's changing: Soon enough, headsets will seamlessly track the whole world through their onboard cameras.
The Mirage Solo shows how well that can work, but I think this first step needs better controllers, a lower price and more apps. Google promises that 60 apps will support the added motion tracking in the Mirage Solo, and several games (Rez Infinite, Bait [a fishing game], BBC Earth Life in VR, Blade Runner Revelations) I've used already use it. But how many will make the leap? Google promises that existing apps could be ported easily to take advantage of the extra tracking, but the Mirage Solo literally stands alone as the only product it would be used for. Of all the many Google Daydream apps you can try on the Mirage Solo headset, there aren't that many that support its extra motion-tracking tricks.
Will this headset track over a larger range, which Google says it could do, in theory? Will new controllers arrive? Will it maybe be able to do mixed reality, blending what the cameras see and what appears in VR? Not right now, and by the time these possibilities arrive, I bet they'll be part of a newer, better headset.
Next year, I bet more headsets use in-headset camera-based tracking. The future belongs to where the Mirage Solo and Google are going. But Oculus, Google, Microsoft, HTC and many others are . Right now isn't the best time to buy a headset to use it, unless you're really, really curious.