Good question. Are you more a programmer or an artist? A7 provides a great engine and language with features which allow you to be creative as a programmer, whereas someone less keen as a programmer will prefer something like Unity or Torque, which provides more modern built-in graphical features with much less effort and an easier content-creation pipeline.

If you can get into shader programming (which is my favourite part of programming, and is quite easy to learn with the workshop) you'll quickly learn that A7 gives you a good interface to innovate and do whatever you want, whether it has been done before or not. This in particular is why I prefer A7 over anything else.

I hope this is helpful

Jibb