I do like that the impact is in "equivalent CO2 tons" allowing comparison across more than emissions. Yes, scaling by cost is questionable but allows simple policy comparisons.
Drawdown seems very interesting overall, but their ranked list is confusing with the top 'solution' being about refrigerants, which amount to no more than a couple of percent gross CO2e emissions. Thats not what most people would expect from a top ranked solution, and potentially detracts from IPCCs seriously worked out advice - that we need to deal most with CO2.