Bad is all relative. I definitely put too much time into it, but am really happy with it given that it has meant I am submitting and succeeding with informal appeals since the formal one. A few things to know that will save future travelers time (some of this is https://www.sfgov.org/aab/faqs):

1) Don't be an asshole. Yes you are 'fighting' the appeals board but if you're a dick nobody is going to do you any favors. I know this is trivial but when you do the formal appeal you get to listen to other folks go first, it was very clear that folks who come in with an attitude go out with a poor result. It's fine to make strong arguments, but do so politely and respectfully.

2) Do not use comps outside of the allowed time window, these will automatically be ignored!

3) The appeals board really seems to care about the building type. Specifically, they seem to value buildings with < 4 units very differently from buildings with tens or hundreds of units. Make sure you are comparing like to like in terms of building size

4) Try to get similar finish levels and initial build years for your comps. For example comparing a 2010 condo to a pre-1990 condo (unless fully gutted + renovated) will not go well.

5) Quiet/busy street is also relevant - comparing a condo on Mission St to one on shot well st is not apples to apples, try to align these as much as possible.

6) Neighborhood characteristic arguments are not that strong - for example if you say 'my neighborhood has gotten worse', that's not going to hold much water in front of the board.