I am using a law firm for my NIW EB2, and I have friends that are also using law firms for their NIW EB2 petitions. But I also know people who applied by themselves. You can do it by yourself but you must understand 100% the NIW prongs and what it needs to be considered a good case for approval. The internet has plenty of resources that can help you self petition. But the questions is, do you have the time and are willing to put all your mental effort to apply by yourself (considering that this is an important decision in your life) ? Having a lay firm that already knows how to apply is easier, less stressful and more convenient. If you have the economic power to hire a law firm, I recommend you do it. They already know how to submit a successful application.

Thank you @Ruben Chavez I am looking to hire Colombo -&Hurd for the process. Just want to hear people's success story with the firm

Colombo is expensive $$$. I also need to find a lawyer.

They handled my case.