IMO - don't get them unless you need them, i.e. you have joint problems.
I think too many people get them because they're the "in" thing or because they think it's going to make them have amazing heels. The purpose of the stirrup is to relieve joint pain, not to be trendy or improve your eq.
I'm going to be getting some. I'm currently not riding because I tore my ACL and fractured my tibia, so I can't even walk let alone ride... Once I can though, you can bet I'm buying some to try and keep the pain down in my knees.