I like being able to keep track of my employees hours/project progress in one place! This makes it easy when reviewing their time sheets etc at end-of week or month - no need go back into multiple spreadsheets trying find what you are looking foor!! It can be slow sometimes if there's alot going through but overall we haven't had any issues with this system so far (we've been using version X currently which has some problems wich they're working out now).
Would recommend checking other similar programs as well; try comparing them all side by size & price range before deciding your best option :) We use AWZ primarily because its great having everything under 1 roof compared 2 seperate systems such an Excel + Access combination where data could get lost over summer holidays / weekends/etc..