Technology never stands still. The last few years have seen a dramatic change in electronic data storage. We have progressed from 5.25" floppy disks to solid state memory on flash drives. The latest development is the Solid-state Drive or SSD. Apple Computer's latest super thin laptop computer can now come with a solid-state drive option. This is similar technology to the flash drives, but on a much larger scale. At the present time, SSDs are substantially more expensive than comparably priced hard drives.
As a comparison there are a significant number of 1 Terabyte (1000 Gigabyte) hard drives advertised for under $200, some as low as $87.00 for an internal drive. To look for a price comparison type the search term "terabyte hard drives" into Google Products. At the same time, the largest solid state drives are about 128 Gigabytes and cost from $300 to over $500 dollars.
It is inevitable that the SSDs will increase in capacity and decrease in cost. The advantages of the solid state drives include less power consumption (runs cooler), no moving parts to wear out, they make no noise and they have a more compact design. There are sources that predict a 1 Terabyte SSD within two years. It is obvious that the fact that the drives have no moving parts makes them potentially a lot more reliable than existing hard drive technology.
The disadvantages presently include their cost, their capacity, the flash memory cells wear out over time and performance of the drive degrades with use. Some of their limitations will be moderated over time and it is expected that they will replace mechanical hard drives, at least for laptop or mobile computing in the next few years.
The good news for the user is that there is no special need to change to a SSD if you already have an adequate hard drive. If you use your computer to travel or to do on site research, you may want the increased durability and lighter weight of the newer drives. All of these changes in technology seem to benefit genealogists for some reason.