If this is your first time here, I suggest you first read my general post about distrohopping. 🙂
The default install is a fully functional system, but with rather few applications installed as default. Personally, I like the default install to be a bit barebones, as I can chose from start what programs I will be using. For me, WattOS scores a big plus on this. However, for a GNU/Linux newcomer, maybe there should be some directions how to find and install software. The choice on a linux system is great, and WattOS is Ubuntu based, so there is a lot to choose from. The repositories are filled with free (and not-so-free) software.
Default web browser is Chromium. I changed to Firefox, but that is a matter of taste. Audacious is an excellent lightweight player for music and other sounds.
There is no dedicated IRC client, nor microblogging. Pidgin can handle that, but I for one prefer e.g XChat and Turpial on a GTK based environment. Again, it is just a matter of personal taste. On the other hand, many computer users use neither IRC nor microblogging, so it makes sense to leave such apps out of the default installation.
WattOS comes without mail client, a rather original decision. Choice of mail client is usually rather personal and long-term, so the lack of any default one makes sense, too. There are many alternatives in the repositories. For lightweight mail app with GUI, Sylpheed and Claws are two well-established ones.
For updating, installing and removing software, Synaptic is provided. It is in the Preferences sub-menu, not under System Tools. I have seen a few other distros putting it there too, which I find slightly illogical and confusing. Update Manager is also installed for easy updating. There is no software center type of application by default. I often find the Ubuntu Software Center very slow, but it is maybe more newbie friendly. It can be downloaded from the repositories. You just have to know about it. Synaptic is not hard to understand, and still feature rich.
I have used WattOS on and off for over a month now, for usual tasks. It is very steady. In the middle of the usage period, I actually upgraded processor and motherboard (both old and new hardware were 64bit), and WattOS continued like nothing had changed (except that the computer became notably faster, of course). Stupidly enough, the new motherboard has ethernet hardware that requires non-free firmware [facepalm]. On a non-free system (as in having at least some non-free elements) like Ubuntu and derivates, it is usually not a problem. It wasn't now either on WattOS. But still my mistake not to check the new hardware more carefully. But that is another story.