Shark IZ840HRW Stratos Cordless Vacuum

Not always. A recurring complaint with the Stratos IZ840HRW is that it stops working within a few months: the motor gets noisy, power cuts out on high, or suction disappears. It isn't universal, but it comes up often enough that it's worth keeping the receipt and registering the warranty as soon as it arrives.

Mostly, yes. The IZ840HRW picks up crumbs, cat litter and pet hair well in most accounts, though a few units come across as weak or lose suction over time. Its infrared sensor raises power when it spots debris, so pickup steps up on a dirty patch.

Easy. Setting up the Shark Stratos, steering it and putting it away are all described as simple. The MultiFLEX wand bends so the head reaches under furniture, and the same joint folds it over so it stands for storage. At 8.9 lb it's a noticeable weight to carry upstairs, less so on flat floors.

It's mixed. Some barely need to recharge, while others find it runs out too soon, especially on high. Shark's up-to-50-minute figure for the IZ840HRW is for ECO mode at the hand vacuum, so floor-head cleaning on higher power gives less. The battery is removable, so you can charge it anywhere in the house.

An infrared sensor looks for dirt and raises power on its own, and an indicator shows when the floor reads as clean. Shark says this improves pickup over running the Stratos in ECO mode.

Shark says the brushroll is self-cleaning and designed to stop hair wrap. The DuoClean PowerFins HairPro head uses two brushrolls meant to dig into carpet and also work on hard floors.

It holds 0.38 liters. That's a small cup, so in a larger home you may need to empty it partway through.