We use GitFlow for features which allows us to build releases by merging in individual features when they are ready. This process works great and the UI for GitFlow is awesome.

However, we find the UI for SourceTree falls slightly short when try to quickly view which features have been merged into a release branch and which have not. For this we fall back to Git Extensions as it has a 'Grey out non-relatives' feature which greys out the lines of all branches that have not been merged into the currently checked out branch (screenshot attached). This is super handy as it gives us a great visual overview of which features are on which release branch. If this were to be added I would transition my whole team to SourceTree as the only GIT UI.