It really depends on the car; some look good, some don't.... but IMO it's not always easy to make one look good.
Yes, makes a huge difference. E.g. an A roadster can work with a Hallock style windshield. A v'd windshield in a 34 sedan, not so much. There is such a thing as trying to put a square peg in a round hole...and you should not try to do that because it's bound to fail.
Not on just just any vehicle, but it looks good here. https://www.jalopyjournal.com/forum/threads/tech-week-making-a-vd-windshield.678500/
In the 70's I loved them, now I cant stand them as I prefer the factory lines that are right in my eye. JW
Won't look good an every vehicle that came with a flat one, but if tastefully done on the right car they look great. DuVall's on a roadster are hard to beat. https://www.kustomrama.com/index.php?title=DuVall_Windshield
Are you referring too a Hallock or Duvall style aluminum windshield or "V" butt glass? If it's the Duvall or Hallock,they work well on most early to late 30's cars,the "V" butt is too street roddy for my taste. HRP
I don't know what V windshield you are talking about, but Duvall style or weird butted glass on 40's cars are both bad decisions in my book.
If a car had stock,it in a "V",I like that. In the 50s one trick that worked with stock "V",was to use the one part Studebaker glass{stock bent V} an put that in to Ford two part V=making it all one. This was thought of as very cool mod an took away any seam in center. On roadsters,with V's added,many are added too far forword on the cowel an look wrong to me,those that are back far enough look good,just not something I'd do may self.