Advice on use of Work Permit advisors

Hello,

My company wishes to apply for a work permit (it is the first time) for a employee originating form outside the EU.

Can people recommend agents/advisors who have provided them with a good service in advising and applying for the permit?

Another question: is it just the same if the employer applies directly? is there an increased chance of failure for putting together the documentation and forms the wrong way or does the Work Permits office give you the chance to put things right?