I'm using Ankh SVN 2.4.11610.27 for Visual Studio 2010 and it works decently enough.
I've set up SourceGear DiffMerge to be able to resolve merge conflicts using the instructions provided here.
I can now right-click a file in my solution explorer and select "Edit Conflicts" and it launches the Diff Merge tool. After resolving all the individual merge conflicts, I save the file and close DiffMerge.
However, Ankh doesn't pick up the returned merged version from DiffMerge and does nothing. When I was using SourceGear Vault previously, saving the changes in DiffMerge would would update the file on disk and then Visual Studio would ask me if I'd like to close/reopen the file to see the changes. Using Ankh, I get no such prompt.
Just to reiterate, I used the instructions and simply chose DiffMerge from the dropdown in the Subversion User Tools options menu. Here is the shortcut that runs for the merge tool:
"C:\Program Files\SourceGear\Common\DiffMerge\sgdm.exe" /m /r="$(Merged)" "$(Mine)" "$(Base)" "$(Theirs)" /t1="$(MineName)" /t2="$(MergedName)" /t3="$(TheirName)"
Not sure if it's the same for SVN, but you may benefit from what I discovered when setting up DiffMerge for use with TFS here.