hi there,
it is hard to summarize PhD life just like that. perhaps it would help if you posted some more specific questions? or else, just read through this forum, that will tell you lots about PhD life.
about your supervisor, well there is no general answer to that either, as every supervisor is different. as the supervisor is very important to your PhD, as you rightly observed, it might be worth doing some "research" beforehand, perhaps talk to current students of your candidates for "prospective-supervisors". but at the end of the day, you can never say for sure. you might just match up perfectly, or it could go all awry, even though others get along well. it is a risk you have to take...