The Polar RC3 GPS heart rate monitor is one of the more advanced HRM available by one of the top manufacturers in this industry. At a price of under $250 it certainly is aimed at performance and professional athletes that are very serious about their training optimization. There are features on this model that you will not find on entry level devices and beginners will probably be overwhelmed by the functionality.
For most people there will be very few if any features that are missing, and with the online services available you will be able to do some pretty serious tailoring of your training regime. Polar call these features Smart Coaching and two of the best ones are Fitness Test and Endurance Program. It is like having the expertise of a personal trainer with you all the time to tell you how well you are actually doing.