I’ve used a ton of different project management apps in agencies as well as freelance. Back in the day I was a Basecamp user, but the product doesn’t really fit my needs anymore (and as a freelancer it can be difficult to justify the cost). I also tend to be partial to ones with a well thought out UI that’s also easy for clients to use.
The two that I’ve found to be a great combo of freelancer friendly and great UX/UI are www.duetapp.com and www.getflow.com. Duet sits on your own server and Flow is a hosted service.
I’m using Getharvest as well. Easy to use. But lacking some features such as calendar, deadlines, to-do lists etc… Hoping to see these features anytime soon.
Getflow does those functions very well though, but it’s missing timetracking for some reason? I think that’s very important, so I never continued with Geflow.
I’m using Toggl.com for time tracking. It has cross platform support, so i can use the app on my mobile as well when i’m working on another computer. Their easy reporting system allows me to make very detailed invoices, which is a pre for me.