I'm not crazy about the single-pivot design on the Extreme X2. If you're planning on changing the fork anyway, you're pretty much looking at 2 identical bikes for almost the same price. The main difference is the frame. That in mind, I would favor the Rainier because I'm more inclined to trust Giant's frames than Haro's. You should ask your shop if they'll cut you a deal on swapping to a different fork.