I've never had an issue with mine. It's always a good idea to compare the new harness with the original just to make sure all the wires are in the correct place. Also tug on the connectors to make sure none are loose.

The last harness I bought took a long time to get built. Year One had all the other harnesses in stock. That one harness took months. The car is all torn apart so it didn't matter. If I was trying to get the car done in a specific time frame, I would have been SOL though.

If you aren't in a hurry, wait until Year One has a 30% off sale. That will save you a good deal of money on an expensive wiring harness.