Comparison of UserControl and WebPart :

Advantages of UserControl:

• Developers are already familiar with user controls which reduce the learning curve.
• UserControls can be used with other ASP.NET APPLICATIONS. Hence reusable.
•  Developing user controls using VISUAL studio is much faster than building it through code as in the case of WebParts.

Disadvantages of UserControl:

• There is a performance overhead as usercontrol use a SHIM as a wrapper to work with Sharepoint.
• Deployment is a bit messy.

Advantages of WebPart:

• Everything is available and CUSTOMIZABLE, i.e. toolbar, behavior, content etc.
• Better performance as there is no shim wrapper.
• Provide a STRUCTURED deployment mechanism.

Disadvantages of WebPart:

• Developers are unfamiliar so learning curve is steeper.
• They are strictly for Sharepoint and won’t work with other ASP.NET applications. Thus not reusable.

Comparison of UserControl and WebPart :

Advantages of UserControl:

Disadvantages of UserControl:

Advantages of WebPart:

Disadvantages of WebPart: