Either chain will do well KMC and SRAM both make excellent chains. You will also want to replace your cassette as well as they tend to wear together and 3k is a lot of mileage for both so I suspect the chain has been past due for replacement. Not always some people are really gentle and somehow get some extra life but usually at 3k it would be past due on both,

I also recommend giving everything a good cleaning off the bike if you can if not carefully clean it all on the bike. I typically use a citrus degreaser or a mix of Rock 'n' Roll Red cleaner and alcohol and just get it all over your drivetrain (being careful not to get anything on your braking surfaces but isopropyl alcohol) and an old toothbrush or the specific cleaning brushes do a really nice job and will help prevent getting old grit and grim in your brand new components wearing them out faster.