I assume you mean A95, as there was no A90.
The only other major difference is the A95 has an LCD that will tilt and twist. A nice feature for certain situations.
Most of the camera makers will produce a series of cameras based on one frame. They are just covering several price brackets.
In February, Nikon introduced 5 new cameras (4600, 5600, 5900, 7600, 7900) They are pretty much the same camera (all are 3X optical zoom), with enough differences to cover certain price ranges.
Only difference I see between these two cameras is the 4.0 mega pixels and 5.0 mega pixels and about $80 in price. Is there much difference between 4.0 and 5.0 mega pixels to justify spending more money?