If the alternative was BobCAD, I'd take the risk.

You can work offline with Fusion, and go online every two weeks or so to update and save to the cloud.
You can also export your models and drawings locally, so you don't have to worry about losing anything.
But I seriously doubt that Autodesk is going to shut it down after all they've put into it.

A free AutoCAD clone is Draftsight, which you can download. If your on a budget, look at CamBAM for CAM.

But an awful lot of people are jumping on the Fusion bandwagon (myself included). Even if you pay for the subscription, you can't get more power for the price.