When talking about "development time", I believe using classes is the most important point. There are others little things you can use for increasing development time even in VFP6 (macros for some repetitive keyboard entries for example). Using version 7 or 8 the intellisense helps even more and the VFP 8's Toolbox is a great helper too! But overall, through the years (and through the VFP versions I used (since 3.0) ) the use of "generic" classes for almost everything in all my projects was the main point for increasing my development time.

About the run-time performance, I don't know any official article about it... but I think we always hope a better performance of a new software version.

see you,