Back in August, I moved a whole WordPress site into a new domain.
The old domain was still alive with only one page and a huge text: go visit our new site at blablah...
During the next one weeks, I checked and rechecked the redirections, one by one, until everything is correct.
Approximately one month later, Google was changing all SERP with the new domain.
Since I also restructured the site to make post categorization better, pages/urls on the new domain even ranked better than the previous domain.
TL;DR#1: get ready to lose traffic within few first weeks, but then, rest assure that big G is smart enough to understand that your site was moved and all will be good.
TL;DR#2: don't worry about the juice if you apply redirections correctly, G index are not that stupid.