I'm very much in favour of a solid hardwood front door and frame. Frames are surprisingly inexpensive.
It will cost you far far less than a plastic door and will be much better. Plastic doors are fundamentally weak and insecure, which is why they are festooned with additional hooks and catches. If you ever hear anyone complaining that their front door has gone wrong, ask what it's made of. it will be a plastic one. Wooden doors can easily last in excess of a hundred years and anybody can maintain them or fit new locks, knobs, bolts, chains etc.
have it fitted by a skilled joiner who will do a better and faster job that a handyman, DIYer or general builder. Ask around for a recommendation. he will probably know a good local door supplier.
including taking out the old door and frame, and fitting your new locks, it will be about a day and a half's work. I pay my joiner £130/day. joiners are not usually painters.
Choose your locks and fittings before starting work. Get at least a British Standard 5-lever deadlock, and use it. If you can afford a BS deadlocking nightlatch as well, so much the better. I recommend three lift-off stainless hinges as they make it much easier to remove the door for repainting or maintenance. It is most important to paint the top and bottom of a door as they are most prone to damp penetration, but they are often neglected as they are difficult to do once the door is hung. It is much easier to paint a door to a first-class finish, or plane it, if you can lift it down easily.