(1) Nope, no displacement mapping. Is on the wishlist on a top place (2) Nope - no plops. Not inside the software. Of course you can select areas to render but can't combine that with an old one inside (3) Lights. You are right, quadratic spots are the same as your squared fallof Bryce ones. Infinite light options on the other hand are way stronger than Bryce ones. You can manipulate almost everything. You can have lights that only apply to specific objects or vice versa - to everything but specific objects. You can define the falloff via a filter that is defined by yourself. You can change shadow intensity and/or use maps for that. And and and. Not to forget you can select the view from lightsource to position it precisely. (4) Stability. Well, this is tricky indeed. Some here do have problems, yes. Some don't. Me for example. It is very depending on your specific system so the only way to find it out really is trying the demo. (5) Of course there are some things that are big benefits. Like Ecosystems. Like native Poser import. Like export features and synchronising with the big players like Lightwave, Cinema, Maya and 3DS Max. (6) What is an issue for some people is the user interface. It is very different to Bryce and if you are VERY happy with the Bryce ui it can be an point. It was it for some Bryce users in the past, that's why i come up with it. Conclusion? Use the demo and get a feeling.

One day your ship comes in - but you're at the airport.