Recruitment companies are there specifically to help you find a job – They already have the contacts so it makes sense to use them. Check if they appear on the general websites or if they have affiliations to professional institutes in your market. If they do, then more than likely they will understand your market and your role and will have the appropriate contacts.
Confidentiality is a big issue particularly at senior level and using a third party such as a specialist recruiter guarantees you discretion.
Any reputable consultancy will be able to advise you on CV structure and tailoring it for the specific roles you want.
Constructive feedback on interviews – You can expand on points during your second interview or if you are not successful, you will get an explanation as to why. This means you get the opportunity to improve your interview skills and learn for the next time.