Not worth it IMO. Braun's the second most valuable fantasy player behinds Miggy, and Hamilton's showing no signs of turning it around. At this point, I'm starting to think he'll finish the year with a sub .260 avg and about 25 hrs. Also, Zimmerman's extremely injury prone.
I agree with AFatGuy - at this point I am starting to second guess whether or not Hamilton will turn it around. Trading a top 3 player for him and a prospect who hasnt played in the bigs yet would scare me a bit.
Definitely a bad deal. Especially in a league that only allows you to keep 4 players. Doing this trade in a league like that would mean that you would have to keep Wil Myers for 2-3 seasons before you can reasonably expect him to be a productive fantasy player, and that's only if he performs at the major league level. Trading away Braun without getting a true star player back just isn't worth it.
You'd deal Braun for something like this: Starling Marte, Freddie Freeman, Matt Latos, and a closer Jannsen maybe. This kind of a package would be ok cuz you'd get a good young combo OF back, a good 1b upgrade an ace and a high end closer.
If you deal Braun you need to make sure you upgrade in your weak areas. or maybe get a Freeman/Kershaw/Bourn back for Braun.