Magento Ajax Cart Pro Extension allow users can add, remove and update products from your Magento eCommerce store in a much easy way, without needing to reload the cart continuously using Ajax pop-up
There are many ajax cart extensions have those features but it depends on how it works with your website to decide it's good or not.
You can refer to this page Magento Ajax Cart Pro by Magesolution to see its best performance.

Get details: https://www.magesolution.com/ajax-cart-for-magento2.html

Some of the prominent features of the extension
Enable/Disable Magento Ajax Cart module
Two options for ajax mode: Fly cart and Show Popup
Display or not display Upsell product on popup
Display or not display "Checkout" button, "View Shopping Cart" link, "Continue Shopping" button
Edit message visible on popup
Specially, Magento Ajax cart extension is designed to not overwrite any files of Magento template. So, you can use this Magento extension for a lot of different Magento themes.
Magento Ajax Add To Cart supports Magento multi-stores
It also supports Magento store with multi-languages
It’s designed and coded with 100% open source code
It’s very easy to install and configure
It’s designed to have Magento Cart UI an absolutely friendly interface.
Source code is validated with W3C standard

For more information about this awesome ajax based cart extension you can check the Demo and User Guide for more understanding.

Demo: http://m3.magesolution.com/builder/women/tops-women.html

We also provide customization services for our extension as per your requirement. You may also visit Magesolution Store that has the largest repository of extensions for the various open source platforms.
If you have any further requirements or suggestions regarding the extension you can always get back to us at info@magesolution.com