This is a little late for the OP, but in my opinion, the skill, experiance, materials, and tools that a professional detailer has are well worth the price, at least for the initial work. The pro I used taped of the stainless and rubber, used two different grades of compound, dilluted it so he could apply it evenly with a brush, and had a professional grade buffer and knew how to use it without damaging the gelcoat. My previous efforts left a lot to be desired and it's hard work.
Now that it's in great shape, it shouldn't be hard for me to maintain it.