No. You'll get it if it passes their tests, but I see way too many complaints of not getting the full value despite being a good phone. If you don't pass their test, you'll get $25 for it. Read the fine print, they don't give you an option to have your phone returned to you, you're at their mercy. While that may also hold true with other retailers/carriers, there doesn't seem to be many complaints about them screwing people around with trades. I'd suggest doing some research on past direct Samsung trade in experiences before making up your mind.
I don't know. The phone turns on and has no cracked screen. No water damage. It does have minor scratches. It also has some minor image retention. I'd just hate to send it in and get only $25 for it.