If you are looking at a twin spindle lathe with twin turrets, you should already have a good understanding of them, and how they work, live tooling is part of a machine like this, it would be worthless without live tooling
Can they crash, any setup is only as good as the programmer, they are not easy if you have never done one before
Each turret is normally only use for the spindle that it is associated with
What is more productive for making 4 axes parts, a 5axes lathe like what you have been asking about, you can bar feed a machine like this, and have finished parts, and don't need a operator to watch over it, only to check parts are in spec and load a new bar stock when needed