looks like there's (at least ;-)) one bug in rep_show_user.php (svn r273): the report seems to get the group membership of users correctly, also the access-rights which where granted to the user directly seem look ok. However: access-rights granted by group membership are not shown at all in most cases and in some cases, they are incorrect. I think I was able to identify the source of the bug:
line 129 should be
$query .=" OR (svn_access_rights.group_id = ".$entry['group_id'].") ";
$query .=" OR (svn_access_rights.group_id = ".$entry['id'].") ";
otherwise id from the svn_users_groups tables is set, leading to incorrect and often no results at all.
Last not least (you already now my addiction to all sorts of sorting ;-) maybe line 136
"ORDER BY svnprojects.repo_id ASC, LENGTH(svn_access_rights.path) DESC";
could be replaced with
"ORDER BY svnrepos.reponame ASC, svnprojects.svnmodule ASC, svn_access_rights.path $pathSort";
If you decide to accept the proposed changes, find a patch attached.