SF2281 fiasco is not all OCZ's fault..if there really is a fiasco. We are supplied a FW from the mothership like everyone else.
Vtx4...the 256's and especially the 512's are not effected by the 50% up and down performance...its the 128's. What we did was make a slowish drive much much faster BUT you have to understand how it works. When you build drives certain configs are slower or faster depending oh controller channel filling etc etc...There is a misconception that all drives/capacities should give the same performance...they will not. What OCZ did this time was bring performance very close across the product range so that "within a few rules" the 128's were as fast as the 512's.
Now we have stated this on the OCZ forum, I can give you all a firmware that will write at the same speed regardless of how much you write...so it works just like everyone else's SSD.
Side effect is write speed comes down quite a bit, you lose that burst speed everyone likes...if you want the drives that way I can see if we will re release FW1.2 for you, being honest no one will like it. And remember this is for the 128's only.
Education time... go read this http://www.tomshardware.com/reviews/vertex-4-firmware-benchmark,3245.html
Now I can not say if this is what we are doing but it makes for a good read...it will help you understand what is possible with MLC nand.