I'll start with the obvious similarities - both are old technology. Back to the specific question, This is the best I've come across for comparison info; stolen from "Sugre" at Hongfire Forums
http://www.hongfire.com/forum/showthread.php/386402-What-are-the-differencet-between-Intel-P67-Q67-C206-Z68
""Q67" supports 14 USB 2.0 ports and allows the connected SATA devices (such as a hard disk) the maximum "goodput" of data at a speed of 6 GB per second. Additionally, the system can use up to eight PCIe 2.0 and older versions of PCI.
Chipset "Q67" was designed for the desktop, and "P67" for high-performance PC, which are preferred by professional players. Because you can use one or more graphics cards "high-end" graphics processor is not equipped with its own interface. Instead, the chipset has the equivalent of extra features for tuning performance to meet the needs of the target group."
Basic but, hope it helps some