Due to problems with 14nm fabrication process Broadwell (a tweaked Haswell CPU) has been delayed. Originally intending to begin production in Q3 2013, Broadwell production is pushed back to Q1 2014. However, these are the "socket BGA" versions of Broadwell which means they are to be soldered into the motherboards for OEMs like HP and Dell. Intel's roadmap indicates that socket 1150 "Broadwell-K" CPUs will be released in Q4 2014. It is interesting that Intel's roadmap does not mention socket 1150 "non K version" Broadwell CPUs at all. After all, it is very unlikely every single socket 1150 Broadwell CPU coming off the production line will be qualified to be a "K" model CPU. Those that can't would typically be binned as lower model Broadwell CPUs.
The CPU performance is likely not increase very much since Intel has not mentioned a word about CPU perforance. The main goal is reduced power consumption and heat. The expectation is that Broadwell can be used in tablets without the need for a fan. Addtionally, iGPU performance may increase by as much as 40%, but it's too early to know what the performance increase will actually be.