Honestly, unless you're worried about not being admissible due to a criminal record or something similar, save your money. I contacted a local immigration attorney when I first started this and he flat out laughed at me and told me I could do it myself (which has proven true).
However, that being said, I do recognize for those who's native language is not English, the wording at times can be a bit confusing. In that case, still, save your money. Use this forum for guidance, as well as the CIC's website for reference.