most individuals in your position pick the m4 because it seems stable and reliable.
Most of the vertex4 improvements that you see in the articles are hardcore read/writes when you're mismashing lots of data, which is not what an individual is doing for just windows and apps in the real world.
Once you've gotten the speed increases with SSD, then you're sort of splitting hairs for that last part of performance for home use.
Also, the fact that they're rewriting their firmware is exciting for new technology- but it also shows perhaps OCZ isn't quite stable or they should've had a good firmware out at the beginning. This is combined with somewhat bad reputation for higher rate of failures for their previous products.
Most people just want their SSD "fast-enough" and then just care that it;s not going to fail on them. So the wait-and-see people would rather go for the m4.
This being said, m4 had an important firmware update also which you should apply (or ensure that the factory upgraded you) before you start your install.