This is one of the best open source projects I've ever come across.
It has automated installers that take care of everything for you that work on both Windows and Linux, its not just some .zip file with a 10 page README.txt that you have to spend the next 3 days messing with just to get it to work. It took me less then 5 minutes to install.
On top of that It is an extremely powerful piece of software and I've searched high and low and NOTHING else in the open source world even comes close to it. I don't know what Alain (comment below) is talking about, since timesheet.php is not even in the same league as this, thats like comparing a Pinto to a Ferrari.
The support forums are excellent and a staff member replies to posts within hours, its not just some mailing list where you have to put up with people flaming you or calling you names if you ask a question that has already been asked.
But that is nothing compared to the VIDEO tutorials that they send you when you sign-up with your email address! These things are amazing. They are extremely detailed, with professional voice-over and everything. I'm amazed that they give them away for free.
I think Alain (comment below) is just complaining for the sake of complaining. The website looks more professional then 99% of other open source projects and it can be downloaded DIRECTLY from SourceForge (Mirror Site URL above) if you don't want to enter your email address and don't want to see the video tutorials. I think you would be crazy if you don't see the tutorials though, because there are A TON of features you will surely be missing out on.