V4 or B5- tough question. On the one hand you already have Bryce 4 so have a little less to learn with B5. Perhaps it is better to know one extremely well than to know both only reasonably well. On the other hand, a combination of B4 and V4 may well give you greater versatility than B5 alone. But as both programs have yet to be released why don't you just wait another month or so until you can read the opinions and see the images of people who have actually used the shipping versions? It's difficult to make such decisions when only specs are available but no real user information or experiences.