Comparative Test of 8 MFCs with Fax: Smeartest
DC tests the behaviour of ink on plain copy-paper.
Markertest: Immediately after printout the lab uses a marker-pen on one line of text, to find out the ink´s stability to moisture.
Droplettest: The lab puts a drop of water on the centre of every colored rhombus. The ink is supposed to stay stable and should not blend.
If you are dependent on high stability of ink, there´s no way around Epson´s MFC. It shines as the winner in this contest.