No expense has been spared in making the Arlo Ultra home security camera the best in the business.

That was my initial impression of the latest flagship camera from Arlo, the market leader in the United States in the wire-free security camera category.

These battery-powered cameras are weatherproof and can be placed inside or outside the home, as long as they are within range of a Wi-Fi network.

After using a pair of them for a week, I am even more convinced that the Arlo Ultra is as good as it gets for these devices.

It offers numerous upgrades over older Arlo models in terms of design and features.

Arlo has reworked the base station (called the SmartHub), which acts as the bridge between the home router and the Arlo Ultra cameras to let users remotely access and control the cameras via the Internet.

The hub is now more compact and comes with a microSD card slot to store recorded videos.

Arlo also said this new hub will support Zigbee and Z-Wave compatible smart-home devices later this year.

The camera chassis and its magnetic mount have been redesigned.

Instead of a fixed spot in previous models, you can attach the mount to the top or the bottom of the camera, allowing for more flexibility. The mount can be attached to a wall or ceiling with screws.

But the biggest upgrade is that the Ultra can shoot videos in 4K resolution. Not only are videos sharper at 4K, they also capture more details that could prove helpful, such as when it comes to recognising licence-plate numbers.

There is, however, a catch. A $2.99 monthly fee (for a Premium Video Recording subscription) is required to upload 4K videos to the cloud.

This is on top of the Arlo Smart Premier subscription service ($143.88 a year), which offers 30-day cloud recording (non-4K videos) for up to 10 cameras, as well as smart features that can distinguish between humans, animals and vehicles and alert users accordingly.

This software service is arguably as essential as the camera. A one-year Arlo Smart Premier plan is bundled with the Arlo Ultra.

If you are unwilling to fork out the extra fee, you can store 4K videos on a microSD card in the SmartHub.

It is less convenient to access the recordings using this method compared with having them on the cloud, but it is probably more secure.

The Ultra can shoot high dynamic range (HDR) videos, a feature that is especially helpful for outdoor videos as it can adjust for overly bright or dark surroundings.

Unlike older models, the Ultra has a built-in spotlight that lights up the view and enables the camera to capture videos in colour, even at night.

Arlo has also shifted the siren from the base station - usually located inside the house - to the camera, presumably so that the noise would startle and ward off would-be intruders.

Other smart features offered by the Arlo Smart service include the ability for the camera to track and digitally zoom in on moving objects such as humans and pets.

This is probably useful for outdoor coverage. But when it comes to indoor use, the field of view offered by the Ultra is sufficient to cover my entire living room such that I do not need the track-and-zoom feature. In fact, the videos shot using this feature did not make much of a difference besides making the video look jerky.

There is also a package-detection feature, which Arlo is still testing, that is supposed to alert users when a courier with a package is at the door. I found this feature iffy when I tried it with the older Arlo Pro 2 camera and it is remains so with the Ultra - at least it did not manage to work properly when I tried walking around in the front of the camera with a parcel.

With its excellent video quality and brimming with features not found in competing cameras, the Ultra is the best security camera for the home.

But it is debatable if it is the best fit for everyone - some features are probably unnecessary in smaller homes and apartments. The biggest sticking point would be its price and the required subscription plan to get the best out of the Ultra.