A lot of it is based on the brand and price.
Until Crucial introduced the MX100's and priced them at half of the market value, the old saying of "You get what you pay for" was relevant. If you went cheap, you got crap. If you spent the money, you got good products. It was that simple.
Even today, the price is important. The best quality SSDs come from Samsung and Intel (though Intel's price point is a bit steep). Nipping at their heels is Crucial, whose MX100 series offers the best bang for the buck and who basically called out the industry by maintaining excellent products at reasonable prices.
When SSDs first came out, they were pretty much a novelty item. Sure it was super fast compared to an HDD, but the SSD's lifespan was far less than that of an HDD and data storage was more reliable on the magnetic drive.
Then they started refining the technology.
An SSD today is not the same as before. The life expectency is MUCH better, with some expected to outlast an HDD.
Put it this way, someone said that if you were to write 4TB to an SSD every day, it would take about ten to fifteen years to become unuseable (all things being equal, of course).
When buying an SSD, there are a few tips to follow:
Brand: Intel, Samsung, and Crucial are the best options.
Size: The bigger the drive, the longer it will last. a 128GB is fine if you're running Linux and have a few programs installed. If you have Windows and a lot of programs, you want a bigger drive.
RAID: RAID 0 is about the only useful thing you can do, and you won't see any real improvements until you get to the 256-512GB disk sizes.
Maintenance: Do not ever, EVER defragment your SSD. Defragmentation moves data from one place to another to organize it in nice, neat little groupings. Flash memory (what an SSD uses) is by nature fragmented. Defragging an SSD does absolutely nothing except waste write cycles.
