You can see for yourself how the results are affected when using a memory intensive program, such as Gordian Knot. Lower rates in synthetics benches do not really reflect in this bench.
We have no complaints. The OCZ Kit works without trouble, but needed more tweaking then Patriot. To gain the best speed you need to tweak your BIOS, because AUTO settings won't give you the best transfer rates possible. In our Gordian Knot benches you can see that the performance gain between 1067MHz and 1667MHz is only 3fps, which is a mere 3.5% in the fastest GK setting. When we did some intensive video-manipulations the memory transfer was not important anymore and the difference shrink to 0.5fps @1333MHz and 1fps @1667MHz, but for the later the higher FSB helped, also.
The major complaint is the price of DDR3. For the speed upgrade from 1333MHz to 1600MHz you have to only pay €50,- more, but at a price of €455,- you pay about 5 times the amount compared to standard DDR2 kits. Even 1200MHz DDR2 kits, which are quite the same speed, will cost you only 40% with prices about €200,-. Still, this memory will get you to 1800MHz+ speed, which is a nice number, but won't add much performance.
DDR3 is far too expensive to justify the upgrade for now. We are eagerly waiting the promised 2000MHz kits, but we fear they will only give a very small improvement at much higher cost.