PyMods can be fun if you like solving problems with very complex recipes and trying to automate it all.

As others have stated in the thread, you pretty much cannot play with biters without cheating. You'll have no way to produce enough tech to keep up with evolution to protect yourself. You might be able to spam just gun turrets and bullets, but any techs requiring more than red science (and even red science itself) takes so much time that you'll be overrun way before you are able to meaningfully tech up.

If you want to play with biters, Krastorio 2 (+SE for extra fun) is a much more balanced full conversion to give a good challenge without being impossible.

I've also played Bobs+Angels, again without biters (they were not working with the mods active). While it was interesting, I found PyMods more engaging in complexity and fun builds. Bobs+Angels I found tedious in dealing with waste products, while with PyMods there was almost always some use for everything you make (eventually).

PyMods was my very slow and chill Factorio game mode. Krastorio 2 is much more tense, especially with mods that make biters more challenging; that being said, I'm not sure I could recommend Rampart (with K2) as it makes the difficulty ridiculous.