We’re still waiting for that magical day when scientists will invent robots to do all our cleaning for us. We have to admit they’re getting closer; you can now buy robotic vacuums and mops if you don’t have the time or inclination to do any cleaning at all. But robotic vacuums aren’t going to clean your sofas, stairs, countertops, car interiors, or pretty much anywhere else besides bare floors and carpets. If your standards are like ours, that’s not going to be enough.

This is where companies like Shark and Dyson come in. Both offer a range of options to choose from that span the gamut from power to portability. If you want the most power you can get in an upright, you’ll either want the Shark APEX DuoClean AX951 or the Dyson Ball Animal 2. But if you want something with more power than a handheld but without the heft, weight, and cord of a full-sized upright, you’ll want a stick vacuum. The best option from Dyson is the V8 Absolute. The best from Shark is the Shark IONFlex 2x DuoClean Cordless Ultra-light IF251. Today we’ll take a closer look at it and compare it to its fellow IONFlex, the IONFlex DuoClean IF201, to see which offers the best all-around cleaning experience. To sum up our thoughts in ten seconds, we’d buy the IONFlex IF251 to take advantage of the dual battery system and buy the IONFlex IF201 if we only wanted one battery. The vacuums themselves are identical. Our full review is below, and you can buy the IONFlex IF251 here.

Where does the Shark IONFlex 2x DuoClean IF251 stand compared to other Shark cordless vacuums?

The IONFlex 2x DuoClean IF251 is the newest member of a dizzying array of Shark ultralight and cordless vacuums. The IONFlex line is the current flagship among Shark’s cord-free options, with the 2x DuoClean models at the top of the heap.

DuoClean is Shark-speak for their vacuums that feature a double brushroll in the cleaning head–a soft brushroll for hard floors and a bristle brushroll for heavy-duty carpet cleaning. The ION in IONFlex refers to the rechargeable Lithium-ion battery system; Flex refers to a joint in the extension hose that allows the vacuums to bend while in stick mode, allowing you to reach under a wide range of furniture and bedding without needing to stoop, kneel, or change cleaning heads.

We’re not sure even Shark knows how many vacuums they have on the market right now, but here’s a quick overview of the closest comparable models to the IF251 that include DuoClean. In the IONFlex line, the only other sibling is the IONFlex IF201, which flexes but only includes one battery. In the SharkFlex line, there’s the FLEX HV391, which also flexes but runs on AC instead of DC power. There’s the Rocket line, which is corded, doesn’t flex, and includes models like the HV382 and HV322. Finally, there’s the ION Rocket IR101, which doesn’t flex but is cordless. If this sounds like model bloat, that’s because it is. We’ve been in touch with Shark about this, but we doubt they’ll change their minds any time soon, as their vacuums are well-designed enough to overcome the fact that there are too many of them.

Pros, cons, and key features of the Shark IONFlex 2x DuoClean IF251 Vacuum

Key features of the IONFlex IF251 include the DuoClean and IONFlex systems described above as well as the inclusion of 2 Lithium-ion batteries that each provide 30 minutes of battery life on extended run-time. We’d estimate it features 115 airwatts of maximum suction (Shark wouldn’t say, so we based our estimates on comparisons to the V8 Absolute, whose value we had ahead of time), the ability to clean bare floors and low-pile carpeting, and and adjustable cleaning  head.

A pleasant surprise is that, unlike Dyson’s cord-free efforts, the IONFlex is also capable of standing upright on its own. It’s 45.9 inches tall, weighs 8.7 pounds on our scale, and has a cleaning path 10.2 inches wide. Its dust cup holds .3 quarts, or .07 gallons at full capacity. You get 3 cleaning tools with the IF251: a pet multi-tool, an anti-allergen duster crevice tool, and an anti-allergen dust brush. Aside from the vacuum and accessories, in the box you’ll also find a pair of ION batteries that take 3 hours to fully recharge, a charging dock, a quick start guide, a user manual, and the warranty information–5 years for the vacuum and 2 years for the batteries.

What’s the difference between the Shark IONFlex IF251 and the IONFlex IF201?

We’ll make this brief, because Shark certainly won’t: the only meaningful difference between the IF251 and the IF201 is that you get an extra battery with the IF251. The extra battery allows you to clean for an hour instead of 30 minutes as long as you remember to keep both charged. Charging both, incidentally, is easy, as you can charge the ION batteries three ways: by plugging in the vacuum with a battery attached, by placing a battery in the charging dock, and by plugging the battery directly to a wall outlet. The charging dock, as a result, is rather unnecessary. In fact, you don’t get it at all in the IF201.

Besides the additional battery and charger, you get slightly different cleaning tools with each vacuum. While both include the duster crevice tool and anti-allergen dust brush, the IF251 throws in a pet multi tool to round out the list while the IF201 adds a dusting brush and wide upholstery tool instead. Frankly, none of the accessories are nearly as useful (or fun to use) as the vacuum itself in stick and handheld modes, so the differences here won’t be noticed by most owners.

How well will the Shark IONFlex IF251 clean up after kids, pets, and spouses?

To summarize our thoughts, much as the APEX DuoClean AX951 is easily the best full-sized vacuum Shark has made so far, the IONFlex IF251 takes the title for their best stick vacuum. It’s not perfect; compared to a Dyson V8 Absolute, it’s significantly heavier, notably bulkier, not nearly as ergonomic, only holds half as much dirt in its dirt bin, and slightly noisier.

That said, it’s just as powerful, and unlike any Dyson, it’ll let you switch batteries to keep cleaning for far longer. It’ll take care of bare floors (e.g., hardwood, vinyl, ceramic tiles, marble, bamboo, etc) or most residential carpets (e.g., Saxonies, berbers, and cut and loops) easily. You’ll also be able to disconnect it in a pinch from the cleaning head and use it in handheld mode to tackle pet hair, dirt, dust, and food on sofas, in beds, on stairs, in car seats, and just about anywhere else for an hour thanks to the swappable battery system. We’d recommend it over the IF201 because of the battery system, which is a game-changer among cordless vacuums. But if you’d rather start with one battery and buy a second (or third, or fourth) as needed, the IF201 will clean just as well, as the vacuums are exactly the same.

You can buy the Shark IONFlex IF251 vacuum here on Amazon. If you don’t need the additional battery and charging dock, you can buy the IONFlex IF201 here.

Canadians can buy the Shark IONFlex IF251 vacuum here on Amazon or skip the extra battery and save some money with the IONFlex IF201 or IF201C here instead.

If you find our research on PMC helpful, you can follow our efforts to keep maniacally reviewing home cleaning tools by shopping through our links above. We promise to keep fighting the good fight against every horror children, animals, and grown, yet messy humans can inflict upon a clean home.