Obviously 890 is better. 890 has two chipset, 890GX and 890FX. 890GX is higher end board and its main feature is support for multi-GPU setup as it supports Crossfire of two AMD cards in X8-X8 mode. Also it is equiped with onboard HD 4290 DirectX 10.1 Graphics which is slightly better than IGP of 880G, HD 4250. Most of the 890G boards come with USB 3.0 and SATA 3 6 Gbps support.
890FX is the enthusiastic level chipset with support for X16-X1 mode Crossfire. It can host 3 or 4 Graphics card in Triple or Quad Crossfire setup. This chipset does not come with any IGP as the target audience is expected to add a dedicated Graphics card.
However, currently they are getting replaced by AMD 900 series chipset with AM3+ support. They are like 990FX, 990X, 970G and 980G