I think the R3000 has replaced the R2880, as it is 4 years old. So I'm out of date when it comes to proper comparisons.
However the black n white is brilliant, it uses 3 key cartridges, they have a different one for gloss and standard too, so I guess that means 4 cartridges but only 3 get used at any one time. It has a really nice ability to avoid colour cast as a result.
Downside is that having 3 black inks to buy doesn't really help the economy side of things, hence why I normally use a different printer!