I would be inclined to avoid that latest idea, the MP190, and stick witht he MP540 if funds will allow it.
As far as I can see, the MP190 has only two ink carts, one black and one with the three colours which is an expensive option ( run out of cyan when when the magenta and yellow are still full and you through them away.
The MP540 has the four tanks and lets you replace individual colours as and when needed.
If the funds can stretch, the MP540 is a much superior machine.