Anandtech posted a review on the Plextor M5 Pro (256GB) SSD
Plextor's strength lies in performance and quality. As we saw with the M3 Pro, they have a firmware team capable of delivering top-of-the-class performance: The M3 Pro was easily the fastest Marvell 88SS9174 based SSD and overall it was one of the fastest SATA 6Gbps SSDs we have ever tested. When looking at NewEgg reviews, Plextor's SSDs have only few one or two-egg reviews, which speaks for many satisfied customers. With the performance and quality combo, Plextor's SSDs are not as price competitive as some other SSDs are, although Plextor is aiming for wider audience with the M5S.Plextor M5 Pro (256GB) Review
Due to our positive experience with Plextor's SSDs, I've been super excited about the M3 Pro's successor: the M5 Pro. Plextor is the first SSD manufacturer to use Marvell's new 88SS9187 controller, which is paired with Toshiba's brand new 19nm Toggle-Mode MLC NAND. I can't lie, I've been looking forward to reviewing the M5 Pro for quite a while. Ever since the M3 Pro review, I've been waiting for something faster. The M5S was merely an incremental update with different NAND and new firmware; it didn't bring any major performance improvements. The M5 Pro should eliminate the possible bottlenecks created by Marvell's 9174 but as there are currently no other Marvell 9187 based SSDs (OCZ Vertex 4 and Agility 4 may be, but there hasn't been any confirmation on the exact silicon), it's rather hard to know what to expect. Given the performance of the M3 Pro, the bar has been set high and if the M5 Pro is faster than M3 Pro, we may be looking at the fastest SATA 6Gbps SSD on the market.