It's funny, I got the upgrade to Carrara, and instead of jumping right in to it I have been messing around with Amapi, and I am very pleased to say that it doesn't have a very steep learning curve, it's just very different from any other tool that I have used. I am hooked on it. I would buy the upgrade to 6.0, put it doesn't run on OS X natively and that is a must since I am almost exclusively running on X all the time. As soon as EOVIA announce that AMAPI 7.0 will be coming out for OS X, I will place my order. Productive is the key word in this modeler. But like very one says here get Carrara and you get AMAPI.