Thanks for posting this.
Most appraisers will never come across in their lifetime an appraisal assignment as complex as this one in Marin City. There is very little good data in the neighborhood (as I have provided) and only bad data in the adjacent areas (as I have shown with the high and low sales in Sausalito). Most any appraisal is going to have areas that can be attacked, not because the appraiser didn't support their adjustments or write enough but because each of those adjustments has such a high tolerance level. You're not fighting over whether the GLA adjustment should be $100 or $150 per sf, which might make a 2% difference in adjusted sales prices. You're arguing over a location adjustment for outside sales that is likely, at minimum, 20% and probably more and therefore has a 20%, or more, effect on the adjusted sales price.
Additionally, based on the 10 years of sales I posted, it's as if the market itself (the buyers and sellers) don't have a firm grasp on what prices should be (the built in noise for the area is just wide). Just in the past year, the "pole" home needing work sold for $50,000 more than the one that was turnkey. Why?
That two appraisers came it at different values in Marin City is no surprise to me although one at $995,000 and another at $1,485,000 is more than I would expect. Given that the market in southern Marin has been as hot or hotter than any other Bay Area neighborhood in the past 3 years, and the two MC sales in the past year were $1,250,000 and $1,300,000, one of those appraisers more than the other may want to revisit the value model they utilized (which is something all of us should do from time to time).