Software quality aspects, like portability, re-use, orthogonality, or complexity are curently not assessible. There are attempts to establish a methodology for software metrics (e.g., [146] [143]) but these are up to now hardly used in any practical software development situations. The same holds true for VISTA. It may be hoped that the future will make available common, established methods for assessing these important properties so that they can be included in important design decisions.