I have read that early model Triumphs were hardware nightmares. It doesnt really make sense to me that they would suddenly get better, but apparently they have. I would worry that he has one of the older ones.
I have to agree with the above - this smells fishy - I love my OV, but bottom line it is an older lower end phone than the Triumph. Heck I just switched back to my OV from my Slider (for sale now in the marketplace) partly because of reminiscing and partly cuz I need some cash.
But a switch from the newest and best to one of last years models is odd.
If you do decide to go for this - I would give him $30 or so at most. I would go somewhere public with free wifi. I would call Virgin right then and make sure that the phone has a clean number that can still be activated. Then I would use it for at least 15 minutes on wifi - use BT, use GPS, plug in headpphones, play some youtube over headphones and the speakers, etc.
Basically a good test drive is in order. I have looked at the Triumphs and have held off mostly because of price and the GPS - which I have read and seen videos showing as a world class turd.
When you are figuring on a price to negotiate - remember that although he might have paid as much as $300 - the Triumph is available NEW on Amazon right now for $220 or so.
Do not give this person any money down over the net for any reason - do the deal with cash in person only.
I will leave you with an oldy but a goody - "if something seems too good to be true, it probably is"