Customized why build a pergola is definitely a plus thing to have as you can produce it in any design and design that you want. Moreover you may also add different functions that you'll require which might not be available in a premade one. But remember that having a custom made one also means you may want to organize more on the budget specially when you want to produce a particular design. Obviously, you still able to modify every thing so that it wouldn't go over budget so you will need to discuss the option after again.
Which means you may even select several substance for a design. This may also produce the style be intriguing and fashionable as different material will give different texture to the shade. This way your back yard will have more degree on the style due to the use of this shade.