Analysis: best SSD per capacity
While a 120 GB SSD used to be very good, this segment is limited to true entry-level models nowadays. Many new SSD-series do not even offer this capacity. A lot of the speed that SSDs are known for is achieved because they can read and write to multiple memory chips in parallel. However, these models often only have one or two NAND-chips. This means that you should not purchase an SSD with this capacity for its performance. The Intenso High Performance 120GB (average price of 56 pounds / 63 euros) is the cheapest product in this segment and in our opinion the most interesting option. If you want a drive that is faster, you quickly get to the point where for about 10 pounds more you can purchase a drive that has double the capacity. This means that an SSD of about 120 GB is only interesting for users that do not demand a lot from their system.
For less than 88 pounds / 100 euros you can also find the cheapest 240 or 256 GB SSDs. That said, you should not be too quick to purchase one of these, because the performance of these cheaper models is not great. This is particularly true for the WD Green- and Sandisk SSD Plus-series. In terms of price-performance ratio the Crucial MX300 (average price of 93 pounds / 106 euros) turns out to be nearly unbeatable: for a relatively low price you can purchase a fast SSD with a lot of features, like hardware encryption. Furthermore you also have slightly more storage capacity due to the 'weird' capacity of 275 GB, which is always welcome. The Samsung 850 Evo (average price of 91 pounds / 103 euros) is not as interesting in terms of its price per gigabyte, and the minimal performance difference is not noticeable in practice. However, Samsung does offer a five year warranty whereas Crucial offers three.
In the 500GB-segment you should also not be looking to purchase the cheapest options - for saving a relatively small amount of money you have to give up on a lot of performance. There are a few models that perform well and have relatively low prices, like the Mushkin Triactor and the OCZ Trion. Unfortunately these drives are only available at a few shops at the time of writing. We quickly end up at the Crucial MX300 again (average price of 144 pounds / 163 euros), which offers a lot of value for money at 27 pence per gigabyte. Competitors like the Samsung 850 Evo (average price of 158 pounds / 180 euros) are a lot more expensive in this capacity.
If you use software that requires a lot of storage capacity or if you want to stop using hard drives altogether, SSDs with very high storage capacity become interesting. The cheapest model is the Sandisk SSD Plus (average price of 263 pounds / 299 euros). Because the controller in this model can write to multiple memory chips in parallel it is faster when compared with lower capacity drives of the same series, but the Crucial MX300 (average price of 269 pounds / 305 euros) is once again the better choice. The Sandisk Ultra II is basically just as fast and has a good price at some shops - if you can find it for a lot less than 264 pounds / 300 euros you should certainly consider this drive.
We only have three participants in the 2TB segment: the Crucial MX300 (average price of 523 pounds / 594 euros), Samsung 850 Evo (average price of 615 pounds / 699 euros) and Samsung 850 Pro (average price of 898 pounds / 1020 euros). The 850 Evo is slightly faster than the Crucial MX300 and comes with a longer warranty, but in our opinion the added price of more than 88 pounds / 100 euros is a bit too much. The 850 Pro has basically lost its right to exist with the appearance of PCIe-SSDs - one of the cheaper 2TB-drives paired with a fast M.2-drive for your operating system and most used software is a better investment for everyone in our opinion, which also results in more storage capacity.