you will mostly use your phone, not so much your computer after rooting. most of the benefits come from apps and themes and ROMS and kernels you can download and install right from the phone.. rarely is a computer needed
many say, it is nearly impossible to brick a phone during rooting. there are so many step by step and existing threads on it, you should be totally fine.
you kind of have to be a **** to not be able to pull it off. there are even apps that can d it for you - EasyRoot (but research it) - and the old school step by step way takes some time and effort, by the thousands have done it.
the only real con is it will make you spend way more time ******* with your phone then you ever really wanted to