I can't comment on the Fusion line of firearms, but I agree with Richard on the courteous nature of Bob Serva.
I sent him a Rock Island Armory .38 Super frame assembly, an Essex slide, and I already had one of Fusion Firearms 9mm match barrels. Bob sent me several e-mails to make certain he did what I wanted. The Essex slide was matte blued and the RIA frame was parkerized, and I let him know in an e-mail I was going to send the gun off once I got it back from him to get it re-blued. He said in order to save me the trouble, he would send it off and get the entire pistol re-blued for $67.00!! What a super nice guy.
I'll post pics when I get it back. My point is, if you needed service on a Fusion arms pistol, I am confident it would be handled to your satisfaction. Bob is one very conscientious person.