Well this is a critical question that marketers face every day when working with their Mobile marketing programs. It is well known that mobile app usage crushes mobile web usage. Mobile consumes a larger and larger amount of people’s free time. The top apps in mobile capture in excess of 80 percent of the total mobile app usage. If you want to capture large amounts of traffic you need to be on the biggest, of the big sites. The rest of mobile apps are stuck fighting for the crumbs left over from the major sites.
If the average company is going to invest in apps, they need to make sure that the user experience offers tremendous value. It solves a real problem and provides content that the user can not find anywhere except from the app. User retention is terrible for apps. Most apps get only used a few times at best. Because there are always new apps coming out the competition for your mobile screen space is just to high for most apps to survive.
On the other hand Mobile web has the ability to reflect your company image to your users, and Google and the other search engines still favor delivering Website results compared to app results in their search engines. It is also easier in general to update the content of mobile websites, as you completely eliminate rewriting code of a complete app for new content.
The cost of Mobile Web is usually much lower than App design fee’s, especially when you get into higher end apps.
If you would like to watch a video on this subject I found a very good one by Rand Fishkin. Here is a link to it. https://moz.com/blog/mobile-web-mobile-apps-invest-marketing-whiteboard-friday