I discovered Paymo about two years ago when I needed a tool to watch how much time I'am spending to my freelance projects.
As I am a journalist worked for Bloomberg Businessweek Turkey and some other major PC magazines I'm teached to dig deep to find the details. If you would make a search on Google about time monitoring and management tool you'll find tons of solutions but let me list the differences those makes Paymo the best one.
1- Paymo has a very user friendly interface. You don't need to spend lots of time to learn how to use it. Just start from the dashboard and continue with Clients, Projects, etc. You'll be able to start using it like you have been always using it.
2- Paymo has PC clients both for Windows and Mac OSX. Those clients monitors everything you have done and it's just two clicks away to assign those works with any projects or tasks.
3- Even if you are working on different projects or tasks at the same time it's really child game to monitor the time you are spending on those different things.
4- It's also really easy to add time that you don't spend on computer (like meetings, phone calls etc.) on your projects or tasks.
5- Managing invoices are easy. Reporting to clients what you have done and how much time you have spend on those tasks is awsome. My clients are really happy to see what they are paying in details even they are not asking such a report.
6- On PC clients you can create automatic rules. A very well time saving feature.
7- Support is great. You'll get an answer almost immediately from the Paymo team.
8- Even I haven't need any paid option (wow thats great) subscription prices are very affordable for freelancers.
9- It needs some discipline but you can watch a big teams work on computer with the support of IT guys. No more social media much more work on PC :)
I can exactly monitor my time spendings on my projects. I am a freelance journalist and I am looking to many times to my social media accounts or checking my e-mails during my works. I can't assign those times to my clients. So they pay exactly for the time I have spend from them. Even seconds are considered.
On the other hand some of my clients pay for me for the tasks I finished. They do not interested in times that I spend to finish my works. For such clients I can watch my time spendings and improve myself to be more productive.