I've owned Vue5I since 3/05, and I personally consider C5Pro the best both for the $$, and in absolute terms. The advantage of the Vue sun is eclipsed by Carraras sun due to the fact that the Carrara sun is a true simulation. The vue sun is more an infinite light.

At any rate, I do presently use Vue, and if one can afford both then they might consider getting both applications. Though, with all the problems I've had with Vue, I doubt I will upgrade to V6I?