To be honest my girls don't currently have unsupervised access to the internet, due to their ages, however that will change as they get older and do more research online. I like that Action Alert provides me with the peace of mind to leave them to it.
My favourite aspect was the email alert function for questionable words or phrases - it's great and you can even customise and add additional words as well as having the option to shut down the computer from a remote location. The Safe Search filter is very comprehensive, it blocks sites containing inappropriate materials or viral threats and again you can add additional criteria to suit your needs.
Action Alert can record up to 60 hours of screen shots and playback videos - I can see how this could be useful when they get older and need to be accountable for their online school hours. It also shows both sides of IM chatting (what your child types and the responses) which is a fantastic protection tool.
I found the program very easy to install (took about 5 mins) and so far haven't experienced any problems with the program (we run on Windows Vista).
I love the ethos of Action Alert and the fact that the company provides the basic program for free just proves their integrity. The basic free version of Action Alert can be downloaded here. The Maximum Protection version (multiple user protection, fully customizable, and has full social network monitoring) is $29.99.
To see what the other crew members thought visit the TOS Blog. Action Alert has also been featured on the Today Show, as well as receiving awards from Disney Parenting.
Disclaimer: I received a free Maximum protection version for the purpose of giving an honest review.