My opinion is, if you got the tools, use them. I did some postwork on my latest contest entry... added some bubbles that I knew I couldn't do in Bryce (others might have been able to, not me). So the 'Bryce purists' might say that it is no longer a Bryce image. So what? I would never try say that image is 100% Bryce created. But I will definitely let it be known that I used Bryce to create it, and it will go in the Bryce gallery, not 2D or Painter or Photoshop, because Bryce was the main tool used. So put me in the category that says the ends justifies the means. If it feels good, do it.