Headed in the other direction (Linux at home to Mac at work) for years now, I can't understand what the fuss is about with Mac keyboard shortcuts. In my experience, I don't find them consistent, useful, or pleasant to use. You hit the nail on the head with alt-tab.
alt-tab is universal. Hell, alt-tab works on Android if you hook up a keyboard to it. Mac is the only thing where alt-tab falls on its face. Even if you remind yourself that you're on Mac and use cmd-tab, it cycles between apps, not windows. You need to use cmd-` for that. I often find myself in a cycle of using 3 windows across 2 apps and it drives me bonkers.
alt-tab is universal. Hell, alt-tab works on Android if you hook up a keyboard to it. Mac is the only thing where alt-tab falls on its face. Even if you remind yourself that you're on Mac and use cmd-tab, it cycles between apps, not windows. You need to use cmd-` for that. I often find myself in a cycle of using 3 windows across 2 apps and it drives me bonkers.