I've been a way from photography for a while and looking to get back into it and heading down some rabbit holes online and came across medium format.

It looks fascinating, but I've gotten lost pretty quickly. I see cameras like the Mamiya 645 for reasonable prices on eBay, but I have no frame of reference for what I'm looking at (with 35mm and digital I have a fairly good idea what's what).

I'm looking for the full rundown on getting into medium format
What should I be looking at for a camera and lenses? What about film? Are the results of medium format worth the cost and hassle? Any other considerations I should be thinking about? Any thoughts, tips, and discussion would be greatly appreciated!