So long as Beckett stays healthy and regains his old form - I think you win this deal. Uggla is an upgrade, and one of the best fantasy 2B year in year out. As long as this doesn't boot a solid keeper (e.g. where you would be in a position of keeping Halladay + solid keeper vs. Beckett + Uggla), I say do this deal.
**As an aside, I would definitely shop Halladay. Everyone will listen, and you can see what value the rest of the league places on him, and get potentially get an even better deal than this.
Good luck, and please help my answer my own Beckett trade question? Thanks.viewtopic.php?t=417537