Lol, I actually went the EIP route to keep my options open.
- hassle free trade-in
- known guaranteed "trade-in" value at time of initial purchase (assuming Apple sticks to a regular 12-month release schedule)
- comes unlocked or can be easily unlocked once paid off
- if after 12 months, resale value via secondary market or trade-in via other channels is significantly higher than carrier trade-in, easy enough to pay off device and resell yourself
Come to think of it, if one has Android smartphones, carrier EIP probably nets higher trade-in compared to selling yourself via secondary market.