It's unclear why the chip was delayed, late last year SandForce claimed the first disks would hit the market in the first half of this year. According to the leaked production schedule, a new B0 revision is expected to start sampling next week and production orders will be accepted for delivery in Q4 2014. This means we'll see SF3700 based SSDs in Q4 2014 or Q1 2015.
The SF3700 can't come soon enough. Serial ATA SSDs have been bumping into the limits of the 6Gbps interface for a while, and the latest Intel motherboards are primed for PCIe storage. So is Windows 8.1, which has native support for the NVM Express protocol designed specifically for SSDs. All we need are affordable consumer drives—and applications—that take advantage.