My old man just bought an i450 Canon and I bought a MP360. For the most part this was due to the cheap ink prices. I can get generic black ink for both for under £2 a cart and under £3 for colour.
The print heads are seperate with those printers (i350 probably the same) which keeps the cart costs down and in theory they should be replaceable though I've not seen anywhere to buy them.
I'm finding the printers very fast and easy to use. I can't comment on the duration of an ink cart yet as I'm still on the first one.
I would have to say that for now I'm a convert away from HP and Epson.