If someone sends you the wrong item you don't get to keep it because it was their mistake. If you don't believe me, wait until your bank accidentally deposits someone else's check in your account.

What the company owes him is an RMA number, free return shipping and the delivery of the item he actually ordered as soon as possible. What they have done is given him the chance to save both himself the time and trouble by asking if he'd like the keep the more expensive item for a substantial discount. (Since it was their fault shipping and restocking costs are all on them, so it is probably nearly a wash for them.)
I don't think that's a bad thing. I just wish I knew enough about the two units to offer an opinion. Joe, have you checked the specs on the Epson site, or Googled reviews of the two units?
Regards,
Joe