FWIW I been using a Mac (mac-mini) as my main computer for the last 10 years or so, and it's a lot less hassle to do just about anything, IMO. I've generally kept a windows pc of some sort too, to run certain software and hardware, though my last windows laptop bricked itself recently. No comparison as to which works more smoothly.
I can't speak to integration with iPhones. Maybe. Might be nice if you use iTunes and the other apple services. I have no idea how iphones work for cycling apps. I don't really like any I've tried with android, but then I prefer to just ride. Certainly iphone is not required if you have a mac pc. I've used an Android smartphone since the beginning. Gmail and all the other google services are cross platform, so it doesn't really matter.