A chisel is not complex.
In today's world, it should not be difficult to use a suitable alloy, properly forge, harden, and grind it, and put a handle on straight. Nonetheless, it seems to be more than most current manufacturers can achieve.
Though some seem to feel that getting four of the five basics right is a good average, the bevel-edge chisels we offer typically meet all five basic criteria. (Sometimes the Marples have slight handle misalignments.)
We have been very pleased with the consistency of our Lee Valley bevel-edge chisels. The grinding is the best we have seen anywhere.
The side bevels are not ground as close to the chisel face as with our other lines. While this might be limiting in a specialized use (like cutting dovetails), it makes the chisels more rigid; the additional strength is highly desirable in general-purpose use. All of our chisels are either flat or slightly hollow on the face.
A slight hollowness should not be of concern. They are easy to lap in the regular course of sharpening. What you don't want is a chisel that is convex on the face.
Good makers aim for flatness or a slight hollow to ensure that they never produce a convex one. All are hardened to Rc58-62.