Euro vs. American hops of same name?

Does anyone have experience using both a European hop and an American version? Examples like Saaz, Tettnang, Goldings etc. Are the differences very pronounced in aroma or flavor?

Full disclaimer here: I know that most of these Americanized version of noble hops are considered very close to the originals, but I feel like I get a bit of a citrusy character from American versions of traditional noble hops. This is a very new theory of mine. I just carbed up a pils that used a bunch of liberty for a mash hop, bittering, and mid boil addition. I used 4 ounces of Czech saaz hops within the last 10 mins of the boil. I didn't expect any citrus at all, but there it is. It tastes amazing, but I was not expecting it at all.

I was hoping for more replys to this thread.Some of the American ones are a whole % point off (alpha acids)from the European ones.I guess a good rule of thumb would be to use European for mild authentic European beers and use the American version if you want a stronger slightly citrusy flavor.