The 550 is smaller than the 650 but it still looks like a full size sink. It fits perfectly in our smaller bathroom. The shape is a little more rectangular and the basin is also more rectangular (vs. Square for most sinks) - which makes the sink look upscale.  

The quality and look of the sink are superb. Does not look cheap in any way - looks like a $400+ sink. 

Bottom line:  very happy with purchase and it exceeded our expectations.