I must admit I only get Bryce (if cheap enough) so i can export the Bryce format models to other more reliable and faster applications.

I got the upgrade option at around 20$ so it was a good deal for me but I always found Bryce by itself to be a bit buggy and slow.

Its just one of those apps, if it works on your system its 'What are you talking about it works fine for me' but if it doesnt your in for a world of pain.