Archicad is purpose built architectural CAD software that has been around for years and was the leading Architectural CAD software globally for some time. It is at the higher end of the price range and is also available for Windows. ArchiCAD and all the architectural CAD software at this level of professionalism does require extensive time to learn and master. It is a professional software product designed with dedicated professional users in mind. Interestingly since 2007, Graphisoft have been apart of the Nemetschek Group who also own All-Plan and Vectorworks. All competitors of each other to some degree, Vectorworks being a cheaper option with fewer features than the powerful ArchiCAD.
Archicad is an incredibly powerful professional product suited for large architecture firms with money to spend. It has a steep learning curve and I would not recommend it for a hobbyist, small business owner or anyone with time constraints, there are far better suited products (Home Designer, RealCAD, Vectorworks) for small to medium sized businesses who would soldem make use of the power of Archicad.