I am involved with instrumented forks and carriage-mounted fork scales, so I have an interest as well as an opinion. Hydraulic derived weights are inexpensive and good for check weighing. They are not "accurate" in the conventional scale sense, being limited generally to a +/- 2% error window in practice. But they are very useful and pay back in a reasonable period. They can weigh very accurately in some applications, on some machines and with some operators. My associates sell a lot of them. For accuracy, loadcell systems are the current performance products. Almost all can weigh with better than 1% error, most are capable of better than 1/2% error, regardless of the operator. To achieve better accuracy, additional enhancements are usually necessary. Tilt sensing is the primary requirement. My associates systems both instrumented forks and carriage-mounted scale elements can provide netter than 0.1% accuracy error with tilt compensation. There are other methods also. One of my associates provides instrumented pins and instrumented chain-links. When looking for forklift scales, be sure to have a good idea of the operating conditions, the type and size of machine and the weighing results you expect or demand. Whether you are checking for a missing case of beer on a standard pallet or loading hay (hydraulics are fine for this) or weighing raw materials remnants or high-value scrap (loadcell weighing), you can find what you need, usually at a cost which can be amortized within weeks or a few months. Even a $12,000 scale can pay back in a very short time. An overloaded truck can cost $10,000, double or triple that. A single fine can pay for a lot of scales. Just one example. I hope my comments have been useful.