Signet collectibles

Hello, my fellow collectors. I was wondering if you guys have any insight on signet collectibles? ian mcdiarmid is taking send-in items through them but I am curious on thier services because I am worried about sending a high end art poster(17.5x26). I was fortunate too have hayden christensen sign for me at galaxycon and I am worried about it getting lost or damaged since I spent about $600 for this piece already. What do you guys think about thier services?