The Apple Human Interface Design Guidelines has a section on consistency which reads in part

Consistency

Consistency in the interface allows people to transfer their knowledge and skills from one application to any other... Ask yourself the following questions when thinking about consistency in your product.

Is your product consistent:

• Within itself?
  
• With earlier versions of your product?
  
• With Mac OS standards? For example, does your application use the reserved and recommended keyboard equivalents? (See “Keyboard Shortcuts”.)
  
• In its use of metaphors?
  
• With people’s expectations?.

Recently Torsten's been changing the user interface components used by RSS Bandit from the DotNetMagic library to the Tim Dawson's Windows Forms controls due to the fact that the former is no longer free as in beer. Given that we are changing the look and feel of the widgets Torsten thought this would also be a good time to rearrange some of the menu options and remove some of the toolbar buttons. I tend to disagree. User interface consistency between versions of an application is very important especially when you consider it messes with the muscle memoryof users of older versions of the application.

Torsten has posted screenshots of the new RSS Bandit UI and is asking for feedback. His questions are phrased differently than I'd ask. I'd ask if users want the user interface to be consistent with old versions of RSS Bandit or not? I'd also ask if users prefer that we keep the old DotNetMagic user interface or move to Tim Dawson's UI components?  

If you use RSS Bandit I'd appreciate your comments.