TechPowerUp posted a review on the Crucial M550 512 GB
A quote from the article:
Crucial's new M550 SSD is based on an updated version of the Marvell controller, which means it no longer uses overprovisioning: you get to use the whole capacity. In our real-life testing we also see a slight performance improvement, which is great, especially considering the M550's competitive pricing.Crucial M550 512 GB @ techPowerUp