Google's streetview is infinitely more useful. I've never used flyover nor has anyone I know. It's stupidly pointless. I can understand some of the order things that Apple does, but not this. Is it cool, maybe to some. But Apple Maps on a whole are best left avoided in my experience.
I like and use both Street View and Flyover. But use them for different things.
When I'm in a new City, Flyover is great for getting a quick and dirty look around - more detailed than a flat map but way faster to navigate than Street View. It was great when I visited Rome 2 years ago - lots of winding alleys that look similar, Flyover helped a lot. Street View in this situation would be slow and annoying.
Street View is great when I have more time and want more detail. Pretty rare that I actually need it day to day but when I do it's really useful. When I bought my house I used it to check the surrounding streets.
I'm glad on iOS I have both.