I've been using TurboCAD/CAM now for over 15 years and currently have TurboCAD Professional 15.2 Basic Edition. While I have tried to stay current with new versions, as a hobbiest, they have gotten too expensive. In addition, I have not found the upgrades to fix problems that I encounter. As a hobbiest, I do not use many of the features and especially the advanced features so I find it odd that some of the quirks still exist. In any event, I would recommend the cheaper option as I would be surprised if the more expensive option will give you any more value.
If you already know a CAD package such as Inventor, you will be disappointed though. But that's why Inventor is so expensive.