If you've read anything about strings, you must have read that you should use StringBuilder instead. "some text" + "some more" + " text" is expensive. I would guess Concat gives you a performance boost similar to StringBuilder, but limited to strings. I have to admit that appending each value individually in builder is bothersome. I know I wanted to find out how much builder helps, so I built a cpu intensive process with accounting numbers. I mixed fixed text with numbers to a string using + logic. Got the actual coding to work and changed over to StringBuilder. Processing went from 40 minutes to 20 minutes. Then I changed the logic to only use builder when I needed to save the stat strings. Cut down to 7 minutes. Then played with the process order and it went to 4 minutes. Needed to buy my second laptop in 7 years to cut it to 2 minutes. :)