Considering a lot of features on the 360 (and probably on the XBOne as well) are blocked by a pay wall (Gold Membership to use Netflix? What a rip off), I would rather use that money to buy a WiiU or PS4. No joke, one of my local stores was selling a used WiiU for $70. So, if the money I get in trade for my 360 is not limited to Gamestop or just the XBOne, I'd rather just get myself a WiiU for almost nothing.
The only problem is, despite how little I actually use my 360, I still have a small collection of games for it that I am still fond of. Not to mention I have some DLC and other stuff that I paid for on it. I almost don't want to give it away just because of that. I doubt I'll ever buy another Xbox console ever again, so it's a tough decision for me...