I commented on this in another thread, but all summarize my experiences with gravity fed brushes.
the HP-CS is a great starter brush, that will do good general work. If you want something to do more detailed work with, I would consider an HP-C or HP-CP/CH. these are good overall general workhorse brushes that still allow for good detail. They're pretty durable, and can withstand a lot of abuse.
I prefer gravity fed brushes to other types of brushes, excepting the side feed brushes, which I feel are underrated and dismissed by many people. In fact, the HP-SBS might be a great brush to consider. however, the reason I like side feed brushes is for control, and the degree of control I like is not always necessary for general modeling.