There are a bunch of comments here that say something along the lines of "F the clones, outperform them. Execution beats ideas, etc." While you should absolutely focus on creating the best product and best service, you are doing your business a disservice by not pursuing these routes and giving your business the best chance to succeed. Don't be shy about using the legal system - it's there for many reasons, including to protect rights and provide a just playing field for everyone.