All in all I think Alonso is the more valuable player (so I guess if anyone "won" this trade it'd be the Eagles), but this is a pretty win-win trade. Nothing like the obvious Trent Richardson robbery.
the Eagles won the trade and it wasn't even close... not necessarily saying the Bills "lost" but consider:
-Alonso is probably the more valuable player
-the Eagles now have about
$50 million in cap space
-this is one of the best RB draft classes in a while, between Gordon, Gurley, Duke Johnson, or Jay Ajayi, among others
-Spiller is now a FA and could easily be signed by the Eagles
-
$50 million in cap space holy balls
the Eagles have the money to upgrade the defense however they want. they have the ability to pull off a Mariota trade and still grab a RB later if they want, but regardless I can't see Chip's offense doing poorly regardless of who's starting at RB or QB.