Let's say that you're making a new game console, and you're not one of the big three (Sony, Microsoft, and Nintendo). You can't afford to take time for developers to get up to speed, because you're already at a mindshare deficit. So you pick a commodity middleware that runs on a lot of hardware, preferably one that already has lots of software and a decent SDK. These days that means using Android, which is why most of the new microconsoles (Ouya, Gamestick, Mojo) are just running re-skinned versions of Android 4.x.
Nvidia's Shield is no different in terms of the underlying OS, but it does change the form factor compared to the other Android microconsoles. Instead of a set-top box or HDMI stick, it effectively crams the company's ridiculously powerful Tegra 4 chipset into an XBox controller, and then bolts on an LCD screen. I like Android, I like buttons, and I spend a lot of time bored on a bus during my commute, so I bought one late last week.
It's a bulky chunk of plastic, for sure. I don't particularly want to try throwing both it and the Chromebook into the same small Timbuktu bag. But in the hand it feels almost exactly like an XBox 360 controller — meaning it's very comfortable, and not at all cumbersome. It's definitely the best package I've ever used for emulators: playing GBA games feels pretty much like the real thing, except with a much larger, prettier screen. I'd have bought it just for emulation, which is well-supported on Android these days.
Actual Android games are kind of a mixed bag. I own a fair number of them, between the occassional Play Store purchase and all the Humble Bundles, and most of them aren't designed for gamepad controls. The Shield does have a touchscreen (as well as the ability to use the right thumbstick as a mouse cursor), but the way it's set up doesn't promote touch-only gaming: there's no good way to hold the screen while the body of the controller sits in the way, and portrait mode is even more awkward.
But if the developer has added gamepad support, the experience is really, really good. I've been playing Asphalt 8, Aquaria, and No Gravity lately, and feeling pretty satisfied. For a lot of games, particularly traditional genres like racing or shooters that require multiple simultaneous inputs, you just can't beat having joysticks and physical buttons. It also helps showcase the kinds of graphics that phones/tablets can pump out if your thumbs aren't always blocking the screen.
So the overall software situation looks a little lopsided: lots of great emulators, but only a few native titles that really take advantage of the hardware. I'm okay with this, and I actually expect it to get better. Since almost all the new microconsoles are Android-based, and almost all of them use gamepads (for which there's a standard API), it's only going to be natural for developers to add controller support to their games. I think the real question is going to be whether Android (or any mobile OS) can support the kinds of lengthy, high-quality titles that have been the standard on traditional, $40/game consoles.
If Android manages to become a home for decent "core" games, it'll probably be due to what Chris Pruett, a game developer and former Android team member, calls out in this interview: the implicit creation of a "standardized" console platform. Instead of developers needing to learn completely new systems with every console generation, they can write for a PC-like operating system across many devices (cue "fragmentation" panics). Systems like the Shield, which push the envelope for portable graphics, are going to play a serious role in that transition, whether or not the device is successful in and of itself.
The other interesting question if microconsoles take off will be whether there's a driver for innovation there. In the full-sized console space, it's been relatively easy for the big three companies to throw out crazy ideas from time to time, ranging from Kinect and Eyetoy to pretty much everything Nintendo's done for the last decade. PCs have been much slower to change, a fact that has frustrated some designers. Are microconsoles more like desktop computers, in that they have a standard OS and commodity hardware? Or are they more like regular consoles, since they're cheap enough to make crazy gambles affordable?
The Shield, perhaps unsurprisingly from Nvidia, points to the former. It's an unabashedly traditional console experience, from the emphasis on graphics to the eight-button controller. It's good at playing the kind of games that you'd find on a set-top box (or indeed, emulating those boxes themselves), but it's probably not the next Wii: you're buying iteration, not innovation--technologically, at least. It just so happens that after a couple of years of trying to play games with only a touchscreen, sometimes that's exactly what I want.