This is the first time I've ever read anything negetive about Fusion. Everytime I've seen a thread opened about them, all I've ever read are stellar reviews. I can chime in and add that they do indeed ship out the wrong parts often, as I too have experienced this. I ordered a slim ambi safety and they sent me a wide ambi safety. I didn't even notice it until my gun was being built up.
My gunsmith also told me that every part from Fusion, the frame, slide and internals were some of the hardest ones he ever had to work with. He had to dedicate hours just fitting the Mag release. He said the beavertail didn't even fit in to any degree. It was definetly not cut to a .250 radius, that's for sure. He said it was definitly very labor intensive to even get the gun built up. His only positive comment was the nice slide to frame and barrel fitting that Fusion did at the factory. Not bashing Fusion, I do enjoy mine, but I wish I would have known that there are some major misses in the QC department.