I agree with the Overall statement of this Post. Regarding a "GiveWell of X" type of organization I believe it would have to function quite differently, ideally only working on-demand instead of doing broadly aimed research for the following 2 reasons:
I love this concept and I really hope it gets the momentum required to really take off!
One minor bug report: I was trying to sign up to GoodWallet in Firefox via my Google account, which caused the website to already fill out [first_name][second_name] as my suggested GoodWallet-pagename. However, this string contained more than 20 characters, which made it impossible to create this wallet. Trying to delete this string to manually choose a smaller pagename did not work, which got me stuck in this step of signing up. Retrying the same process in Chrome worked just fine. (Let me know if you need more details to recreate the bug/if there is a dedicated way to report these sorts of issues properly.)
As already suggested by many other users, I also believe that increasing the tax efficiency is crucial. I am no expert what the best way of achieving this would be. However, I feel like my own likelihood of using this tool would drastically increase with its (perceived) monetary efficiency.
Hey fx,
even though I definitely cannot speak on behalf of EA as a whole, I would like to add my 2 cents to this discussion. In my opinion, this sort of question is difficult because it aims at comparing different donation outcomes, that are very hard to compare. (That is a very common problem in EA and I believe that any answer given will be somewhat controversial because of this.) How many years of school attendance generated are equally good to one death prevented? How many times would you have to stub your toe such that the combined pain is more than keeping your hand in boiling water for a second? In a lot of cases, comparing different interventions in Animal Welfare combines mutiple of these "controversial comparison steps". For example, when comparing the open wing alliance (OWA) and the shrimp welfare project, we need to decide
Rethink Priorities worked a lot on the first problem.
Unfortunately shrimp do not die in a matter of seconds. Their death lasts an average of 20 minutes. Crunching these numbers, MHR comes to the conclusion, that these different interventions are surprisingly close in their effectiveness. Considering just how controversial each intermediate step was to come to this conclusion, I find it quite reasonable that people with slightly different assumptions think, that the shrimp welfare project is much more cost-effective.
I also wanted to use the opportunity to link this post from Benthams Bulldog, which I found quite nice, even though it doesn't exactly match your question.