you can purchase the software, you get 2 free autorigs every week if you wanted to use it. But the software is good, its getting more flexible with updates. But im not to familiar source engine but its possible you can use both softwares, I do have the full version and its pretty good, and it will work with source engine. Also if you need a biped use the autobiped script for 3ds max or maya. To me the software is still in process of development and will get more features, but you can import your own content and everything into the software with the default body models in there. So to me the software is a 5/5 rating imo and worth the money, you just have to give mixamo a chance.