It's all up to you. If you don't want to go back to China and willing to start everything in Canada, then go for it.
There is no difference whether or not you have an agent to represent you. All cases are processed by Consulate, not by any agent.
Unlike US GC application, at least laywers should write a cover letter, which is very important for the application evaluation by INS officer, nothing that any agent can do for Canadian immigration application except filling the application forms based on your draft. I don't think it makes sense to hire someone just doing "copy and paste" without any brain work. But again, it's up to you, they do make a living by this.
There is no difference whether or not you have an agent to represent you. All cases are processed by Consulate, not by any agent.
Unlike US GC application, at least laywers should write a cover letter, which is very important for the application evaluation by INS officer, nothing that any agent can do for Canadian immigration application except filling the application forms based on your draft. I don't think it makes sense to hire someone just doing "copy and paste" without any brain work. But again, it's up to you, they do make a living by this.