When comparing Fink vs Conda, the Slant community recommends Conda for most people. In the question“What are the best Mac package managers?” Conda is ranked 7th while Fink is ranked 8th. The most important reason people chose Conda is:
They are fast and reliable as they do not need to compile before installation.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Will be familiar to apt-get users
Fink is based on apt-get making the transition to anyone used to Debian-based environments easier.
Pro Install from source
Pro Packages provided as binaries
Installed applications don't need to be compiled and built on the system.

Pro Binary installs
They are fast and reliable as they do not need to compile before installation.

Pro Allows for multiple environments
It is great for developers since you can easily switch between complete environments with different versions of packages, for testing and development.

Pro Open source
Conda is open source and on Github, so if you see something wrong you can fix it and submit a patch.
Cons
Con Doesn't support newer macOS versions
Doesn't support macOS Big Sur or Monterey. Says it's "coming soon."
Con Pre-compiled packages are often out of date
It happens often that the user will come across out of date, pre-compiled packages. This can impede on using new features released in apps due to using older releases.

Con Doesn't have everything
Conda is relatively new and has a smaller user-base, so the set of packages available is limited.
Con No way to resume downloads
Any download that is canceled or interrupted will have to be started over from the beginning as there is no built in solution for resuming downloads.

Con Installs huge collection of default unneeded libraries
