I recently had my one and only custom (tell the gunsmith how you want him to do it) gun done by Harrison Design.
viewtopic.php?f=6&t=7814 As my luck would normally have it, there was a problem. It took a while to figure out, but once we identified the problem, John didn't back up a bit. The problem caused some repairable damage to some substantial (and costly) parts. John gave me the option of either having him repair the damaged parts, or he would buy brand new replacements (upgrades, at that) out of his pocket. After talking with him, we agreed to repair instead of replace.
I just received the pistol back today, and although I haven't had the chance to shoot it yet, I'm sure it'll be perfect. John emphasized how much he tested it, and I know he hated that it happened.
Anyway, just wanted to let everyone know of my experiences. Harrison does indeed stand completely behind his work. I'm certain no one here would have expected to hear any different. If/when I scrape together enough spare change to have another 1911 built, I know who I'll be having do it.