SourceTree Log view is not very usable with large numbers of branches/changesets with complex dependencies. Improvements to the UI would go a long way to putting this right.

1. Have a way of searching for a branch by partial match (could incorporate this into the Jump to: field fairly easily: dynamic/selective drop-down like gmail label searching).
2. Sort branch list (in left pane) most recent first (same order as log). Most times I'm looking for a recent branch and this is furthest away!
3. When selecting a branch in list - move view log to that branch immediately (even if already there - for visibility).
4. Highlight the ancestors of the current branch in the graph part of the log view.

Incidentally, selecting a branch doesn't always take the log view top the branch – even if I Update To that branch. But this is clearly a bug; I'll file it.