Just read a very interesting article "The Quiet Death of the Major Re-Launch" on UIE about applying small incremental changes to your web site instead of the old method of redesign the entire thing with a massive roll out often sending your visitors it a tail spin of confusion. Even though we don't build web sites as such we build web applications this is the same approach we apply. This way we can actually get changes and improvements out to your customers much quicker and faster. Also testing and bug fixing is quicker and simpler as we can focus on smaller sections not the entire platform.
Our findings show that consistency in the design plays second fiddle to completing the task. When users are complaining about the consistency of a site, we've found that it is often because they are having trouble completing their tasks. On sites where users easily complete their tasks, the users seem to pay little attention to glaring inconsistencies, often telling us in their ratings that the site was indeed very consistent.
This sings loud and true to me as we have found the same. Some of our applications are lets say design challenged with different fonts, poor colour combinations, buttons that don't look like buttons, etc. Users don't raise design as an issue as application allows them to get what they want done and gets out of their way. Other applications we have built have not been as easy for the user to get what they want done and makes them think "where's that button for xyz". With these applications the issue of design consistency is a concern.
Obviously design is a very important element of any application or site but being super critical of the layout can sometimes just get in the way or your users. The application is great to look at but to actually get the task done maybe compromised.
What has your experience been?