When it comes to capacity, SSDs for computers are available in 120GB to 30.72TB capacities, whereas HDDs can go anywhere from 250GB to 20TB. When measuring cost per capacity, HDDs come out on top, but as SSDs drop in price, this will become less of a differentiator for HDDs. However, with SSDs, you get much more work done per server which results in fewer devices deployed to get the same output as an HDD. The result? SSDs have a lower TCO (total cost of ownership).
Reliability is defined as whether data is stored as intended, in an uncorrupted state. SSDs in general are more reliable than HDDs, which again is a function of having no moving parts. That’s because, without movement, SSDs aren’t affected by vibration or related thermal issues.
SSDs commonly use less power and result in longer battery life because data access is much faster and the device is idle more often. With their spinning disks, HDDs require more power when they start up than SSDs.