I mailed a title due to a vehicle refinance and it was lost in the mail. I waited 30 days and then went and filed for a duplicate. After filing, about the time the duplicate showed up, I got a call from the credit union saying they got the title noted that the it had been circulated between post offices quite a bit because it has multiple time stamps and all. Well I had to send in the duplicate because the original was canceled by then.
I ended up making duplicate car payments which was a mess and then trying to get a refund and all... yea.
Save time and money and do it certified from the get go.
Certified is the best bet. Recipient has to sign for it and then you have proof that the title arrived at its destination. I've found its best to cover one's rear in these types of situations.