Remember that you will usually pay a premium for new construction, where you might possibly get an existing home that needs a little TLC for considerably less.
As for older homes, well, they can be great, or great pains in the butt. Older homes tend to have a lot more character and often do exhibit better workmanship and materials. However, you will be dealing with old wiring, old plumbing, and assorted other "old house" idiosynchracies. Plus, the older homes tend to be relatively inefficient insofar as utilities are concerned. This is easily remedied by blowing in new attic insulation and putting in a high-efficiency HVAC system. People tend to a lot of money into windows and doors while ignoring the attic and HVAC systems. That's bad because appx 60% of your heat migration is through the ceiling of your home, and it's the single easiest and cheapest place you can make a diff in your utilities. Extra attic insulation will usually pay for itself in around two years via savings on your energy bill.
Brad