Good Insulating Doors
Wooden composite doors may be cheap and practical, but they are not good at insulating and are not weatherproof. On the other hand, uPVC doors are more expensive than wood composite ones, but are more durable and can withstand the elements for long periods of time. Even uT frames are more expensive than steel and aluminum, but they offer you higher insulation benefits compared to wood composite and vinyl.
If you are building a home, you will find wood composite doors to be less expensive than other types. But if you want to convert it into a studio apartment or a home office, then uT frames would be a better choice.
For small or medium sized homes, steel doors are the best. Although they are not as sturdy and durable as other types, steel doors are still better than aluminum ones.
As far as style and color are concerned, you have to think about the type of room you want to build or renovate and then buy the right doors for your space. If you need a double-walled or triple-walled one, then go for steel or aluminum while wood composite will do the trick.