They're made very cheaply from what's usually an excellent steel, 1095. The edges are almost always very poorly ground, and will require substantial work to get them right. 1095 is ordinarily quite tough, OH usually heat treats in a way that accentuates toughness over strength -- which can make the knives extremely difficult to sharpen. This is more true of newer OH than older. But not always true in either case.
The handles are crude at best, but you can make them a lot better with a good oiling.
Over the years I've owned or tried a few OH that were just awesome, some that were usable after a lot of work, and some were junk. Pig in a poke, but they're so cheap you really have nothing to lose.
On the other hand, if you're looking for dependable, professional use cutlery at a good price you aren't going to get better value than Forschner Fibrox or Rosewood(!), or one of Dexter's professional knives. Dexter's carbon knives are very inexpensive and are light years better than OH in terms of knowing what you're going to get.
Hope this helps,