When it comes down to making a decision for Exterior Doors, Metal or Wood, there are some thoughts to consider.
Nothing quite says tradition more than the solid character of a wooden door. They tend to be solid by design, heavy in weight, artistic by manufacture, and reliable for many years. However there are some weaknesses inherent in wooden doors. Hinge attachments can become worn out from repeated action and stress. Exterior conditions can impact the longevity of the painted, varnished, or urethane finish. The most common problem facing wooden doors is their nature to expand when exposed to moisture causing doors to bind, and become difficult to open, or close.
This being said, let's not forget the pure beauty of a wooden door. The solid, secure feeling it offers, and it's flexibility with designer hardware installation and attachment.
Metal doors may save you cost, and will offer you a consistency where wooden doors may not. They are designed, and manufactured to be a perfect fit. Hinge attachment wont wear loose from repeated action. Doors are solid enough to dismay any intruder from breaking in, and locks are not easily removed, or broken out.
The downside with metal doors seems to be their design aesthetic and ability to be creatively finished. Metal doors will require priming, and painting in a solid finish. No staining, or wood grain to encourage here. Only solid colors will do, and the application with metal doors should always be sprayed on. Brush, sponge, or roller painting on metal doors inevitably will show lap mark's and look unprofessional. Also beware i that most metal doors do not have crisp, hard edge design contours found in wooded raised panel design doors. Also, metal doors are pre stamp-cut for lock installation. There is no flexibility here with regards to designer hardware installation or placement.
So there are considerations to be made. Beauty, traditional design, and the flexibility with designer hardware installation found with wooden doors. Or the durability, consistancy in demension, and cost savings found with metal doors.keeping in mind that both door types will require finish maintence from time to time.