Some Afro hair wigs tend to be made of human hair which gives a much more realistic quality to the hair. It also takes a lot longer for it to become frayed and tangly, which is from experience what happens with synthetic hair wigs. The upside with Human hair wigs is that you can straighten them, curl them, wash them and even dye them if you wanted to, and the maintenance would be exactly the same as your own hair. The downside is as the lengths get longer, it tends to get more expensive. To kind of get around this though, I started making my own wigs, pieces, extensions etc. Or you could buy a shorter one and add extensions and pieces as you would your own hair.
It basically depends how often you're going to wear it, and how long you want it to last. If its a one time, or a short time period thing then go with a synthetic/man made wig, but if you want it to last with quality in tact and want to be able to straighten and curl as you please, then look into human hair or a human hair blend which is 50% human and 50% synthetic usually.