Some real basic answers for you:
Strengths: Industry/government standard. Superior analytical functionality
Weakness: Relatively high co$t, somewhat buggy, and a somewhat steep learning curve for advanced functionality
Ease of use: Good, depends on what you are trying to do...
Intuitiveness: Good, but again depends on what you are trying to do...
Level of functionality: Superior to anything else on the market
What is it that you need a GIS to do, and what other options are you considering?