I haven't had to do this. However, even though I would love to have the best looking in the market. I would go with what I can afford even if it is not from the car's manufacturer.
When it comes to replacement, i will prefer the official manufacturer ones, because they seems to be costly, but the quality wise, cheaper ones does not last for a long time.
I personally don't think it matters where you get them. Anything can look fine. It really depends on how picky you want to be about them and how much you are willing to spend. I think anything is fine, as long as you have them
I don't like the look when there is no wheel cover at all. I also don't like the official ones-I just swapped mine to some really beautiful black covers.