What I like about your contracts particularly is the clear payment terms. When I let my clients sign the contract they acknowledge my terms and I never have discussions afterwards about this sensitive subject.
This really happened to me: For a new client I made a super nice mock up that was rejected. The client told me he wanted to go for another designer because he ‘didn’t like my style’. A few weeks later I saw my mock up being turned into a beautiful website. Learned the merits of a contract the hard way!