Use Team -> Synchronize for HG project.
If there are any incoming changesets then it is possible to check the changes by using "Open it in compare editor".
The change is not merged yet. So, the local version should be on left side as usual in Eclipse (with CVS and SVN it works like that).
Currently, newer version is shown on left. But should be shown on right.
Also, preference General -> Compare/Patch -> "Initially show ancestor pane" is not working as expected.