1. As Optimised images are there which help in making lightweight web pages.

2. There is pentagonal fitting which ensures maximum utilization of visible area.

3. Best Think is that viewport ensures that all content is equally legible and displayed correctly and entirely on different screen sizes. Elements of viewport adapt web pages to the screen's length and width, which results in displaying entire content correctly even for mobile devices. Review collected by and hosted on G2.com.

As there is massive growth in no of devices, the challenge is to check the dimensions of different devices and adjust the content.

There is difficulty in deciding the pixels as small-screen mobile phones can have more pixels than old computers. Review collected by and hosted on G2.com.