I use Sync but I haven't paid for it. I turned off all the options in the cookie banner so all I see is a grey box where ads would be and you quickly just don't even see it after a lot of use.
If it were a one off payment of like £5 I'd pay it, I bought it for Reddit, but I can't justify the cost.
If you're a really heavy user then it might be worth it but there's so many great alternatives out there then I think it's hard to justify.
A little bit, in the same way that any man made structure does. But they're quite peaceful to look at and compared to a nuclear or coal plant they're way better to look at.
I wouldn't like to see them in an area of outstanding beauty, but I'm cool with them anywhere else.
Slight nitpick: they're wind turbines, not windmills. Windmills are used to grind things down, like wheat into flour.