When remodeling a kitchen, should the base cabinets go in first, and then tile around them, or should everything be ripped out, the floor installed and then the cabinets installed.

Is it ok just to ask cabinet company people to just come out and give me estimates? How do I know if I am getting an accurate estimate? How many estimates should I request? How much information do I need to give the estimator? I am concerned about "offending" companies ...