I like that this is not complicated to use, it's easy for anyone with an Instagram account to implement. It makes sure you are getting real people who will interact with your posts. The only downside of this tool is that sometimes your follower count doesn't seem accurate at first glance, but they might be inactive later in another day or week.
However if used correctly (follow them as many times per hour), then there should be no problem when viewing their profile view. This has really helped