Well I think alot of really big boards are holding off waiting for vb4 to get its bugs taken care of. They are not rushing.
The changes in Photopost Pro 7.0 with vb4 are merely cosmetic. The kind of things your looking at on a big board is performance and I dont think the changes in 7.0 have anything really to do with performance. The big change in 7.0 is true SEO
urls. The vb
4.0 support is some switchs to define whether you have vb4 and load the appropriate template set. So really performance would probally be similar to 6.2 series really. Just my .02 cents.
Working as closely with Pro 7.0 that I have I know there are no major core code changes other than SEO