Well, yes they're "cheap" as nuke-em says. All-metal TR technology that dates to the early 1970s. Not at all "power-house" deep-seekers and TID's like we are accustomed to today. However, the reason why they're still being made and sold, is NOT because they intend to compete on depth, cutting soils, TID's, etc.... Their benefit that some still buy them for (in addition to being starter kid units), is because they have a unique ability that none of the modern "power house" TID machines have: seeing through small iron. They are like the old Compass 77b's in that regard: They inherently don't see small iron, in their all-metal mode. Ie.: nails null and don't give a signal. However, if you put a coin or conductive target under the nail, you will get a clear and easy beep. In fact, up to 3 or 4 nails. If you try that with today's great discriminator deep-seekers, you will "mask", and not hear the conductive target hiding under the nails.
But the benefits end there. In all other ways they don't compete. They don't cut bad minerals, they lack depth (6" perhaps on a coin), they have no other form of disc (beyond passing small iron), they're difficult to keep balanced over rough terrain, etc...
For a ghost town type environment, and for things like where a house burned down, or under porches, etc.... they will outperform today's machines though.