S3D major cons are: it is not free, not open source and there is no demo to test the product.
However, S3D is A GREAT PRODUCT. I used it for a year now and it is a much better slicer than Makerware.
- slicing is much more quicker
- slicing gives better results
- you can change EVERY parameter of your print (by object, by layer)
- you can save your parameters (i.e. : print using brassFill on a Replicator 2)
- default parameters by printers and materials will give you a good result and a good starting point
- you’ll be able to monitor your print if you let your computer connected to your printer
Of course, you’ll perhaps find open source softwares that will do the job. However, S3D is ready to print “out of the box” (no compilation, no parameter) and its interface is comprehensive and clear.