I have been using snapchat from past 6 months. I have noticed various kind of issues in my 6-month span. it crashes a lot. it basically lets you take pictures and share them with your friends by the mean of story.
concept - its an innovative social networking app. the concept changed when they introduced the stories feature, a short 10 sec video or a simple photo that can be shared and no one can have the access to view that other than your friends. from that point of time, they gathered a lot of attention. now, most of the social networking sites are providing this feature so this app becomes unuseful to me.
design - its design hasnt changed much over the years and thats boring. snaps can be taken quickly but the overall system is filled with lags. its difficult to understand for the new users. it takes time to get used to it.
features - its main feature is the screenshot notification, if someone takes a screenshot you will get a notification. video calls are available. face filters are there as well.
usefulness - this app provides you with a lot of things but now every social media site is providing the same so it becomes unuseful to me. it drains a large amount of battery. its slow and lags too much. I suggest not downloading this app.