This is my experience (i.e I will let the decision for you)
I did it all by myself. I was very careful about my case. But it was tough. Preparing convincing affidavit, supporting documents and testimonies from friends back in COP was a pain. It took me too much time to file my case. But i was lucky enough to get approved within six weeks of filing.
But if you failed to convince the asylum officer at the interview and your case is send to IJ(immigration court), there is no other option. You must have a lawyer. But it is going to be tough for the lawyer to make sense out of the mess. So better to have lawyer at earlier stage.
But i can't stress more: if you are going for a lawyer, get a GOOD IMMIGRATION LAWYER not lame lawyer. I have friends who spent much $$$$ on lawyers just get screwed up even up to Federal Court. These BS lawyers, they don't have time for you, makes you write your won case, the don't carefully review your documents for consistency etc. They were just BS. So be careful on what type of lawyer you getting, if any.
It's all up to you. Make the decision out of your situation(i.e. education, asylum base, friends,availability of concrete supporting docs from COP,nature of work etc)
If you double think on any of these, strongly recommend having a GOOD IMMIGRATION LAWYER!
Good luck!