There are so many variables to your question, that it is hard to give a straight answer. You can start by making a list of what you want in a new residence. Then follow up with desired vs. not desired list of existing homes vs. new/custom homes. I'd say spend about 10 minutes doing this, that will help you identify your major wants. By limiting your time to 10 min max you'll give yourself a good starting point to look at both options.
What area(s) are you considering and do you have a home that you're looking to sell first? If I can be of any assistance to you please feel free to contact me.
Mark Baysden, AICP
Ready Real Estate