Haswell will take up more die space than Ivy Bridge does, and that change translates into a higher materials cost per CPU for Intel, since it won't be able to manufacture as many Haswell CPUs on a single wafer. Haswell's modularity mitigates this disadvantage somewhat, however: Intel can build many different Haswell products, targeting lower-power niches with smaller versions. Even better, Haswell is well positioned for Intel's next-generation 14nm manufacturing process.
Most of the performance tweaks to the main CPU are evolutionary advances over Ivy Bridge's capabilities. At the same clock frequency, users may see performance improvements of up to 10%. The big gains are in power efficiency and graphics performance. Improvements in power efficiency will enable laptops finally hitting all-day battery life in Ultrabooks, while GPU improvements will give mobile users reasonably robust game experiences on the go.
Haswell may have more impact on Intel's bottom line than any CPU in years. The wide range of products supported by the new CPU's modular nature and power efficiency will likely encourage manufacturers to develop a wide array of Haswell products. Users will benefit from having more choices than ever in mobile and desktop designs, with improved performance and longer battery life.