A bit of what I said on DRB:
Joyce is a young, power-hitting corner outfielder with good defensive skills. His minor league stats are pretty impressive, considering he's been young for his league. He'll swing and miss (and strike out) but his walk percentages have been consistently over 10% throughout the minors. Dave Cameron compares him to Jayson Werth, that seems like a pretty good comparison. He's under team control for six additional seasons, and he's only 24 years old.
And on Edwin:
Based on what we know at this moment, the Rays win this and it's not particularly close. Jackson has the physical tools, and the arguments have been stated constantly, but at the end of the day he's yet to show the results or even the processes that reflect on the potential. Thank goodness he has more value to some than I imagined.
In case you couldn't tell, I like the deal for the Rays.