It's easy to use because it has all you need in one place! We are able fix problems as they occur instead waiting until we have time set aside when there may not be enough hours available due too many issues with our customers or projects needing attention at once (which can sometimes make scheduling difficult).
I haven't found anything about WHI i dislike yet but if anyone knows let me know so please feel free!! My team loves being part of this process every day which makes their jobs much easier than before using other systems/methods used by past companies where people were only hired yearly -.-.