This has been an all-Mac household since 2005 (well, I kept the old Windows machine around for about a year after I bought my first Mac but then one day finally wiped the thing and donated it to a charity shop as I hadn't touched it, didn't want or need to touch it, once I'd gotten the Mac and had familiarized myself with it).
I did use Windows at work when I was still working but once I completely retired that was the end of that for me.
I'm not into needing to create and work with design or graphics projects and by choice and skill set inclination stick strictly to photographic shooting and then editing the images I shoot, and for that I do use various software programs (listed here in MR in another thread about that topic). I didn't use iPhoto and I don't use the current version, Photos, either, as I prefer managing and editing my images more extensively and differently than that program offers.
I will add that I am still a work in process when it comes to editing and all that -- for a long time I resisted as much as I could but eventually began to explore the previously-ignored possibilities inherent in some editing programs that I found, wow, DO make a difference in the appearance of the finished edit! There are still many retouching/editing skills that many people have which I probably never will acquire unless I take the time and develop the patience and discipline to learn them......