Code review tool recommendations - replacement for crucible?

Hi all,

I'm looking for pointers to review tools that work with git (obviously), and can deal sensibly with bigger reviews. Things we need:

- Ability to split (set of) commits into multiple reviews,
  so parts of changes can be reviewed by the respective owners
  (or assign different reviewers to different files/subtrees
  in a review).

- Tracking of files (or changes) already reviewed (due to the large numbers),
  and of the handling of issues found so far.

- Support incremental reviews, not just e.g. over the content of a
  pull request (bitbucket) When review comments are processed people
  want to be able to only review that change, and not to be forced
  to find that change in the entire previous changeset without
  the tool's support.

We were mostly content with atlassian crucible so far, but it simply fails to index[1] our large product repo (5+ Gb) so we switched to just give it diffs to review, and it fails to properly display renames, and fails in a few minor but annoying ways in dealing with these big reviews.

Any pointers?

- Andreas

[1] Crucible seems to be svn-centric, and the mapping
    from git to svn changesets they use internally
    apparently is O(n^{too much}) - just indexing
    a new branch identical to an existing one takes
    hours here.