I know about how good is Cerberus, but even for a cheap price I wasn't going to get it since I am lazy to buy using credit cards.
But at least Lookout comes with the basic features.
I have given it a try, here is the story:
1) Here is the home page, mylookout.com :
2) Here is the login page, after creating my account from the android app:
3) Here is the dashboard:
Note that the device was automatically added to the list of devices to be protected.
4) Now here is to find the missing phone:
5) Clicking on Locate helped me to successfully find my phone's location. As you can see, you can zoom in and out and to switch views (Map/Satellite). I also tried to sound an alarm, which worked even when the phone was in Silent Mode. The alarm is quite loud, which turns off after a minute from its start. You can stop it by turning down the volume or switching off the phone (if turning down the volume and the setting to vibrate while ringing is enabled, it will continue vibrating until the alarm stops). After turning down the volume, I tried to see if it starts the alarm with sound again and that worked without a problem. I don't know if the results vary from device to device.