I've got Bryce 5.5 and want to know which is the best Bryce or Vue.If I buy Carrara it's enough for nature renders? Thanks.

Attached Link: http://www.e-onsoftware.com

Carrara is also available as a trial. You can also check out the Backroom, especially the category 'Comparing Vue and ... ' for past discussions on the subject. The bottom line is that the answer to your question depends so much on subjective views of what makes 'the best' software that the only way to answer is to download trial software and make your own opinion.

You should also check out the galleries for all 3 and see which has images that are closest to what you're interested in rendering.

Tho carrara 4 especially has good terrain and sky. If you try some complexity with trees you will be rendering forever. I feel that other outdoor objects would be more of a challenge in c4. With plugins you can do more, but it is more all around or complete than bryce or vue unless you go vue 5 I, which is a whole other ball park even still for modeling you would probably need something else. Bryce and Vue limit file support. All the commercial companies tend to do this which can be very annoying.