For storing large files or doing full-system backups, an external hard drive with a large capacity is your best choice. We found generally positive reviews for the WD My Book (Est. $115 for 3 TB). Available in capacities of up to 4 TB, it uses a USB 3.0 connection and is also backwards-compatible with USB 2.0. Professional tests consistently find that its USB 3.0 connection transfers files very quickly, and its fanless design lets it run quietly without overheating. Reviewers also give it points for its easy setup and sleek looks.
The My Book gets somewhat inconsistent reviews for reliability. In over 300 reviews at Amazon.com, we found few complaints about drive failures, although some users say the software that comes with the drive is glitchy. Editors of The Wirecutter also report that the My Book "has one of the lowest failure rates of all the drives we researched and tested." However, in more than 300 reviews at Newegg.com, we found many complaints about drives that either broke down within the two-year warranty period or were defective right out of the box. Several users say the problem is with the drive enclosure rather than the drive itself, but since the My Book automatically encrypts all data that's placed on it, it's impossible to recover the data even if the disk is intact. Users also gripe that when you return a defective drive to WD under warranty, the company replaces it with a refurbished drive rather than a new one.
The Buffalo DriveStation DDR (Est. $140 for 3 TB) is another solid performer in professional tests This drive has an unusual twist: it combines a standard spinning-disk drive with a DDR RAM memory cache to speed up the rate at which it writes files. Reviewers say this design makes it faster than most standard drives at a much lower cost than a comparably sized solid-state drive (SSD). However, it's not clear that the DriveStation DDR actually outperforms the WD My Book in terms of speed. While Laptop magazine says in its review of the My Book that the Buffalo DriveStation DDR is faster, PCMag.com reports in its review of the DriveStation DDR that it couldn't beat the My Book's speed in a drag-and-drop test. On the whole, it seems there's little difference between the two speed-wise. Moreover, the DriveStation DDR doesn't come in a 4-TB version, and its 3-TB size is somewhat more expensive than the WD drive.
Reviews for the Buffalo DriveStation DDR at Amazon.com are extremely mixed. It gets only 3.4 stars overall from about 100 users, compared to the My Book's 4.3 stars. While owners say the DriveStation is amazingly fast, we also saw many complaints about disk failures. Several users say they returned one defective drive (paying the $30 cost for shipping) only to have its replacement fail almost immediately. Moreover, owners say Buffalo's customer support is appallingly bad. Users complain that they ignore emails, make no attempt to solve problems and are rude to callers. We did not find enough reviews for this drive at Newegg.com to determine whether users there had similar problems.
One drive that gets consistently strong ratings for durability is the ioSafe Solo G3 (Est. $360 for 3 TB). This drive's high price tag is due to its extraordinarily sturdy construction, which reviewers describe as literally bullet-proof. The manufacturer guarantees that this drive can withstand both fires and floods, and it backs up this promise with a year of free data-recovery service in the event that the drive is damaged. (For a fee, you can upgrade this coverage to three or five years.) Professional reviewers describe the Solo G3 as "practically indestructible," and users are impressed with ioSafe's incredibly responsive customer support.
All this security comes with a cost, however -- and not just in dollars. The Solo G3 is built like a safe, but it's also as heavy as one, weighing 15 pounds. While most owners find it very easy to set up and use, it's not the fastest drive available. In professional tests of transfer speed, it consistently lost out to both the Buffalo and WD drives. It also isn't available in a 4-TB size. Most reviewers say that for the truly paranoid user, the ioSafe Solo G3 may be worth its cost, but for most owners, a faster and cheaper drive will be more useful. For less than the cost of one Solo G3, you could even buy two similarly sized WD or Buffalo drives and store two copies of your data in different locations.