pip is so easy, but unfortunately i've found that if you add package signatures to requirements.txt, pip chokes on it when installing it later. And subdependencies aren't always named perfectly, e.g. they might specify ~=1.4, and a subdependency that what was once 1.4.0 is now 1.4.27, and incompatible or compromised.

conda is so heavyweight installing whole pre-approved builds. and the command line options I find extremely frustrating.

I need supply chain security and perfectly reproducible builds, so poetry was the only real option.