Fiddler Everywhere is much more advanced than the classic version, but the price is not the only reason why users don't upgrade from the classic version.

 

User Interface

The user interface does not include native components like Classic Fiddler, which clearly degrades performance, reduces usability, complicates the user interface and certainly makes it difficult for new users to use this tool.

Apart from that the interface grouping is quite bad, for example I want to use Composer when monitoring live traffic, but this is not possible, Fiddler Classic has no such problem.

Also, considering user habits, while everyone is familiar with the operating system interface, the Everywhere user interface requires some getting used to.

Some features that are available in Native UI but not in the Fiddler Everywhere UI;

• Drag & Drop Features
• Ability to do other things while monitoring live traffic (Better multitasking)
• Keyboard integration is very bad (As you can see in the gif, the directional keys don't even change the selection, and therefore the delete key doesn't work as it should, and if you press the delete key while selected, it completely removes the selection instead of selecting the next one.)
• Fiddler Everywhere uses its own Context Menu, which is frankly terrible in terms of user habits and ease of use, it really annoys me to see the opening animation of the context menu every time.

I would expect the interface to be more practical in a programme that is constantly and actively used, and I would prefer the interface to be native rather than working with the browser engine.

(UI is the biggest reason why I didn't switch)

 

Missing Features

FiddlerScript and Add Ons support is not available. 

 

General Feedback

Fiddler Everywhere feels like a downgrade, not an upgrade, and I say this as a Fiddler Classic user of over 10 years.
If you were considering releasing a paid version of Fiddler Classic, I would probably subscribe, but not to Fiddler Everywhere.