Once set up, there's a lot to like here. The B535 WebBox can get up to 64 devices online at once, which is more than most people should need. Its also notably double what the Huawei HomeFi can manage, though it only matches the Huawei AI Cube.
If your priority for a 4G router is a fast, reliable connection - which it should be - then the Huawei B535 (also known as the HomeFi Plus) is easily one of the best options available.

Its fast too, supporting download speeds of up to 300Mbps (37.5MB/sec) and upload speeds of up to 100Mbps (12.5MB/sec). Those maximum download speeds match the Huawei AI Cube but the upload speeds here are double the 50Mbps offered by that device. Thats because the Huawei B535 WebBox supports Category 7 LTE, while the AI Cube only supports Cat 6.

Currently, on Three you can expect maximum download speeds of around 100Mbps (12.5MB/sec). That's significantly below the B535's theoretical maximum speeds, but it's future-proofed for when speeds increase in the coming months.

Its also far faster for both uploads and downloads than the Cat 4 Huawei HomeFi. So in other words, if speed is all you care about then this is the best 4G home broadband option from Three.

But theres more than just speed here, as it supports both 2.4GHz and 5GHz Wi-Fi bands. This is another fairly standard thing in routers, but not always found in 4G ones with the HomeFi only supporting single band 2.4GHz WiFi.

Dimensions (mm): 219 x 138
Modem: 4G
Colours: White
Ethernet ports: 4 ethernet ports
Download speeds: Cat 7, up to 300Mbps
Upload speeds: Cat 7, up to 100Mbps
Wi-Fi specs: Dual-band 802.11a/b/g/n/ac (2.4GHz and 5GHz)
External Antenna ability: 2 x SMA Antenna connections
Power: Mains powered

What's in the box
1 x Router

1 x Power Cable 

1 x Network Cable

1 x Manual