Unfortunately mamba doesn't support working behind proxies (so it's a non-starter in most corporate environments) and it's anecdotal but I've had it fail and crash much more so than conda does. It is faster indeed, but there's the other aspect as another poster points out: there's now Mamba and Conda, so instead of having one standard, we now have two. Plus, mamba can't be used for creating and managing environments, so you still have to do 'coda env create ...' for example.