I am a long time brycer (started with v2.1 back in 1996) and it took me some time to give Vue a real try.

I tried Vue 1.2, then 3 and could not get past a few tests. I was used to Bryce and the Vue interface looked ugly and unintuitive in comparison. On top of that, it was quite buggy compared to Bryce and some features had obviousely been copied on Bryce.

I started using Vue with V6, mainly because Bryce had not been developed for a long time and lacked essential things such as soft shadows, realistics skies and ground vegetation. 
I got used to Vue and rarely looked back since then.

A few years ago, I did a feature comparison based on Bryce 6 vs Vue 7.
http://www.virtual-lands-3d.com/bryce-vs-vue.html

Many things have changed in Vue since then. The viewport previews are much better since V8 and the flickering I talk about is almost gone. The terrain editor is better (though I still feel the Bryce one was excellent)

Some things are still the same though, but the number of unique features of Bryce (those Vue does not have) has continued to dwindle.

One thing though. I considered myself an expert user of Bryce, having delved in the Real World Bryce 4 books and tried to overcome its weaknesses in every way I could. I used light arrays to make soft shadows, custom objects to make grass, HDRI skies from photographs, terrains to model objects. Bryce is easy to learn and you can ultimately feel you can master it.
On the contrary, Vue is becoming more and more a 3DSMax like product, with loads of features everywhere and loads of numerical values you have to tweak, test, tweak, test to get results that many times are far from what you would expect.
Even following excellent tutorials like Dax Pandhi's for instance, does not guarantee you will get the same results.

You waste considerable time with Vue (I feel) because of this. As much time as I lost in Max tweaking render parameters in Mental Ray.

The manual is in the same league as the one of Max: it describes every function individually, but you don't learn what every slider does in practice.

Vue has a classical interface with loads of unhidden math. The Bryce interface was made by Kai Krause and the teams of Metacreations who pushed useability to its very limits, hiding the figures and letting the user play with it.

This has to be kept in mind as well as the price difference that is now enormous.

Fantasy pictures, free 3d models, 3d tutorials and seamless textures on Virtual Lands.