3D Engine and Game Development

..well..if you compare Unity with B3D, then dont...Unity giving you freedom to see actual things you have to code in b3d or pretty much everything majority of use to deal with(basically renderers), so,once you are familiar with javaScript, wich is really easy, its beauty and charm to work with Unity..i mean, inside you got terrain editor, drag/drop objects, dynamic shadows, water, shaders, texture simply load and assign to objects and set up properities on the fly(you see it in real time)..and basically even props, I upload from my 3Dsmax machine in to folder and poop..Unity reload refresh it for me automaticaly...basically, its removing stress from your neck about setting up scene and whatever...and leaving you to focus on to game itself..once everything is done simply compile your game to platform you aiming for (PC, MAC, Web, Iphone and Wii support comming..mmm..)...but to answer your question, i think im not relevant, since i just started with Unity again after version 2.x pop up..before i hated it (I had it but never used), but now with 2.x version is whole different world...anyway, you should ask taumel for precise answer..as for me, i picked it up quite fast, and documentation is extraordinary for it, plus you can download whole source code for completed platformer game with all media, animations and so on, so you can easy see whats going on...