And I heard from another member that the large national firms provide $100,000,000 E&O coverage --- which he says is "the" big advantage - and explains why it is almost impossible for a single appraiser or even small outfit to compete with these large commercial appraisal firms. My LIA is almost $1200/year for $1M/$2M coverage. Also, if you do get in trouble, a large firm can provide far more support than a small firm - or especially what you could provide yourself. Also, you will have to put up working with a 25%-45% commission. - It is not an easy way to make a living.
If you are going to work for such a large firm, that will always be your only alternative, - so why not just work for the government to begin with?