Of course, the ultimate question is: How well does the NES Classic Edition actually work? It's nice that it has a clean interface and a cute physical aspect, but if the emulation of the games themselves is garbage, who cares? Nintendo definitely doesn't have the best track record in this regard: NES Virtual Console games on Wii were well-presented but too dark, they were stretched slightly on 3DS, and they look downright godawful on Wii U.
You won't find that to be an issue on the NES CE. It features excellent game emulation; so far I've only spotted a handful of discrepancies between my game experiences on original hardware and what Nintendo (reportedly its European Research & Development arm) has put together here. Everything moves quickly, smoothly, and responsively. Music and sound effects are excellent; I didn't notice any instances of audio distortion or off-key sounds.
Colors seem to be spot-on (the video I streamed yesterday looked more blown-out and bright than the games appear in person). The second stage of Castlevania was particularly telling; different versions of hardware (including the Analogue NT) tend to output its brick tiles in a deep, bruise-like shade of purplish-brown, but on the NES CE it lacks the blue cast and appears as more of a pure, earthy brown. Color tends to be a sticking point for the NES hardware, since it didn't have a fixed color palette in the traditional sense, and the emulation process involves a lot of best guesses and approximations. Nintendo went with a faithful and visually appealing choice here, and it looks great.
Likewise, pixels scale up precisely, with no filtering, darkening, or smoothing. As far as I can tell, the NES CE only outputs at 720p — I couldn't get my video capture device to record at 1080p — but since that's an even multiple of the console's innate 240p, it works well. The system menu does allow you to choose between "true" pixel mode, where all pixels appear square, or 4:3 mode, where pixels are stretched horizontally to reproduce the typical proportions of a standard-definition television. In 4:3 mode, the stretching does have an impact on the appearance of the game and you'll spot distortions if you look carefully... but I found them to suffer from less shimmering and screen-wide distortion than the 4:3 options on either the RetroUSB AVS or the HDMI-capable Analogue NT. Whatever algorithm Nintendo went with here for scaling, it worked out nicely.
You have one other visual display option: A CRT mode that attempts to duplicate the look of an NES connected to a tube television via RF cable. It looks pretty terrible! Which... I guess is the point. The picture is fuzzy, slightly distorted, and even features a bit of flickering and bleed at the edges of colors. It's faithful, but kind of an eyesore on a large TV. Your mileage will undoubtedly vary.
As I mentioned, some games do appear to have been very, very slightly modified. You'll still notice hardware quirks, like the flickering pixels at the upper left edge of the screen in many games, and sprite flicker can still be pretty intense in places. However, certain effects display differently now. Select a robot master from the main menu in Mega Man 2 and the screen flashes to white once rather than strobing rapidly multiple times — a minor change no doubt implemented due to epilepsy concerns. I also feel (though have not tested this carefully) that certain instances of slowdown have been minimized or removed. Again, in Mega Man 2, the spiked plungers in Metal Man's stages typically cause enormous slowdown, but here they just make the action drag slightly. So, while Nintendo has strived for accuracy and fidelity, it seems they've also done some tweaking to scrub out some of the more egregious annoyances of the era. I can't imagine many people will mind.
Perhaps most importantly, I didn't notice any particular input lag in terms of play controls. Although HDMI and HDTVs inherently suffer from a frame of input lag under the best of circumstances, I didn't notice any major shortcomings in terms of the games reacting to my commands. Famously twitchy sequences like the boxer tells in Punch-Out!!, the Quick Lasers in Mega Man 2, and basically the entirety of Ninja Gaiden didn't give me any particular trouble as I played. I don't have a Digital Foundry-style science lab set up in my office to give a full post-mortem on frame lag, but I can say that I have played a lot of these games in the past year on a high-end, lag-free CRT, and the NES CE feels pretty much on par with that experience.
Without question, the NES Classic Edition gets a strong recommendation from me.
To qualify that, you need to approach it for what it is. Do you want a way to play any NES game on modern televisions? Do you want tons of display options, fine control over audio levels, infinite save states, and other ultra-granular features? This isn't your solution. Systems that offer those things exist! But they do not exist at a $60 price point, and certainly not with a top-flight selection of NES games already built in.
The NES CE is not meant to be the serious collector's go-to for NES gaming. Virtual Console offers a wider selection of NES games on any platform. The Analogue NT gives you an embarrassment of options for playing your games. But 30 NES games on Virtual Console will run you $150 (on top of the cost of the system you choose), and the Analogue NT costs much more than that. Even the RetroUSB AVS, which is a fine device, will run you $200 with shipping.
Meanwhile, the NES CE provides a simple, plug-and-play experience for $60. It doesn't contain every great NES game, and not every game in this collection is necessarily brilliant... but you get 30 very nicely emulated classics that represent a great sampling of the NES's best along with a nicely made piece of hardware and an excellent controller. The NES CE could definitely stand some refinements — longer controller cables, for one, and real manuals rather than online manuals activated by QR codes — but as a pick-up piece for casual classic game enthusiasts, retro-curious gamers, and anyone who wants to relive some fond childhood memories, you'd be hard-pressed to find a better all-purpose NES sampler than this.
The real question, of course, is whether or not you'll be able to find it in the first place. That remains to be seen, as preorders have been extremely limited and Nintendo has a habit of under-shipping its hot holiday tickets. But at the moment, Nintendo would probably benefit more from big sales than frantic hype, so I'm hoping the NES CE won't be hard to find. It'll be a perfect holiday gift for lapsed and casual NES fans.