Sometimes you just want someone to tell you which product to skip and which to buy. It's especially tough in saturated markets, so I ran head-to-head tests on two leading smart plugs to find out which one is really the best.
The ideals: flexibility, affordability and unobtrusiveness.
Test 1: Features
Both iDevices and the Insight Switch boast a lot of features. You can schedule them, track energy usage data, and control them from an app.
Both of them also respond to voice commands like, "Turn off the kitchen lights" -- Belkin with Alexa and iDevices with Siri. Belkin doesn't work with Apple HomeKit, but iDevices now has a skill on Amazon Echo ($80 at Amazon.com), so you can control it using similar phrases to Siri's (see update, below).
If iDevices edges out Belkin for voice commands, Belkin hits back when it comes to energy usage tracking. Both devices display energy usage and estimated expenditure over time, but the Insight Switch organizes that data into a more intuitive interface.
After trading blows, it seems like the iDevices Switch might be beating the Belkin WeMo Insight Switch in terms of features. But Belkin has one more trick up its sleeve: IFTTT compatibility.
IFTTT (IF This Then That) is an app that connects hundreds of devices and apps, allowing any one of them to trigger any other one. For a smart plug, that could mean any number of creative "recipes," including switching on the lights when you come home from work (using geofencing), turning on a space heater when a room's temperature drops too low (using a smart thermostat ($93 at Amazon.com)), or switching on an air purifier when an air quality alert is triggered (using an air quality monitor).
A connected plug is made to be flexible, to turn any pluggable device "smart." And while both iDevices and Belkin effectively offer their own smarts, Belkin's Insight Switch taps into the collective integration platform that IFTTT offers -- and it makes all the difference.
Most flexible: Belkin WeMo Insight Switch
Test 2: Price
Price isn't just about being cheaper; it's about being appropriate. For instance, a gadget might cost $10 more than a competitor, but if its features are significantly better, it could have a better price.
Luckily deciding on the better price between these two smart plugs is easy: the iDevices Switch costs $50, and the Belkin WeMo Insight Switch costs $45. Belkin won the flexibility competition, and it's cheaper -- leaving it with the best price.
Most affordable: Belkin WeMo Insight Switch
Test 3: Design
For aesthetics-minded consumers, the spreading infestation of shiny-white plastic gizmos in homes isn't exciting -- it's annoying. Ideally, retrofit gadgets like smart plugs will blend in even as they offer useful features.
The iDevices Switch looks sleek. It has a colorful LED light strip on a chic white plastic face, and the outlet is hidden on one side. The Belkin WeMo Insight Switch, by contrast, looks like a protuberant outlet -- perhaps odd to perceptive visitors, but generally unassuming.
Although I don't love either option, my inclination is toward the latter, simply because I don't want to orient my home decor around a smart plug. That said, users will have to decide for themselves which look they prefer.
Being conspicuous isn't just about aesthetics, though. Both the iDevices Switch and the Belkin WeMo Insight Switch look relatively small, but they also both have a bad habit of getting in the way. Belkin's Switch blocks the outlet above it, and iDevices blocks the outlet beside it.
Neither of these plugs are perfectly unobtrusive, and neither has outright bad design.
Least obtrusive: Tie
If you prefer Apple HomeKit as a platform, then the iDevices Switch might be a better fit for you. But if you're open to other options like Amazon Echo, the Belkin WeMo Insight Switch is the better overall product. It's more feature rich, in large part thanks to IFTTT compatibility, and it's more affordable.
Overall winner: Belkin WeMo Insight Switch
Editor's note, January 20: An earlier version of this story incorrectly stated the iDevices Switch didn't fully integrate with other Alexa-controlled devices. The text has been changed to properly reflect the nature of its Alexa integration.
Smart home compatibility tool: Find out what smart home platforms work with your existing kit and vice versa.