The folks at Fine Woodworking Magazine have done tests to evaluate the merits of 17 high end chisel sets. The URL for the review is:
http://www.taunton.com/finewoodworking/ToolGuide/ToolGuidePDF.aspx?id=2616Quoting the summary published in the above URL: "The range of chisel prices prompted Rex Alexander to review 17 high-end and low-end models, including Japanese chisels. He limited his evaluation to 1/2-in bench chisels, also called bevel chisels or cabinetmaker’s chisels, and did controlled and uncontrolled testing at his bench and at a lab to gauge how well they held an edge with repeated pounding. He talks about how they are made, discusses different types of handle fittings (such as socket and tang chisels), and explains differences between hand- and machine-forged steel. Alexander tested the chisels on white oak, curly maple, and cedar, and he reports on which tools performed best. The results may surprise you."
What I found from this review is that the most expensive chisel does not necessarily yield the best results as shown by the test. The expensive laminated steel Japanese chisels did well but the English steel chisels did not rate as highly on the toughness test. The two that stood out in my opinion were Two Cherries and Hirsch, a pair of German chisels made in Remscheid since 1858 which held its edge and were ranked 4th and 5th, I believe, just below the Japanese chisels at about half the price as the Japanese counterparts. Interestingly, also, Lie Nielsen's chisels and its cryogenically treated steel was not part of the test.