The context of the proposed data structure is more important for evaluating how effective it is at maximizing performance.<p>This context includes not only the characteristics of the (typical) systems using the data layout, but also the typical use of that structure (read heavy, write heavy, some mix).  The cost of memory is also an issue.  For a typical end user program the bottleneck is almost always going to be the user.  For larger scale programs or more performance intensive areas of a program (E.G. graphics languages or other large data operations) different tradeoffs should be evaluated.