If you're looking for a portable hard drive then the Silicon Power Armor A66 offers everything you need. It comes in a good mix of capacities ranging from 1 TB to 5 TB. Some power users might want more, but for the vast majority of the audience even 5 TB is probably overkill. Thanks to support for the USB 3.2 Gen 1 interface, the A66 is able to maximize the potential of its drives—the interface allows up to 500 MB/s.

In our performance testing we saw transfer rates of slightly above 100 MB/s, which aligns with what you can realistically expect from any HDD-based enclosure. The latest portable SSDs do offer considerably higher transfer rates, but also cost more. Still, if you are regularly transferring huge amounts of data, you should probably consider a portable SSD, especially when it's for work where time is money. On the other hand, an HDD-based solution offers tons of capacity for very little money—you're basically getting 5 TB of HDD storage for the price of 1 TB SSD storage, which is definitely tempting if you're willing to wait a bit on your transfers to complete.

A unique selling point of the Armor A66 is its ruggedized design, which is IPX4 certified and thus protects against splashing water from all directions. Silicon Power is also advertising that the drive meets "military standard" requirements. To be more precise, the A66 is tested to MIL-STD 810G Method 516.6 Procedure IV, a tiny subset of all tests. This specific test involves a drop of the unpowered drive from a height of 1.2 m—not a problem thanks to the rubber shell. Still, if you feel you'll be exposing your drive to such hazards regularly, you should absolutely opt for a portable SSD as those drives are much more resistant to shock because they have no moving parts—you can smack them around even as they operate and they'll be just fine. For the vast majority of users, the main issue is dropping the drive while handling or during a bumpy car ride, which is no problem for the Armor A66. For that extra peace of mind, I still wish Silicon Power had designed their drive with IP57 or IP68 in mind: "sealed against dust" and "suitable for immersion in water."

Priced at $120 for the 5 TB version and $60 for the 2 TB version, the Silicon Power A66 is very competitively priced; it is basically one of the most affordable portable HDDs on the market. The differences are small, however, and drives like the WD My Passport Portable, Toshiba Canvio, and others are not that much more expensive. In this market segment three years warranty is the standard, with five years quite rare and expensive and more common for portable SSDs. Considering Silicon Power uses high-quality Seagate HDDs, there's no reason to worry about buying from a smaller vendor like Silicon Power.