If you give a look in the thread "Green Lasers", you'll find five nice reports:"Opto 170mW green laser quick video & 6 balloon pop", "Another green laser on the way", "Some of my cool Laser photos", "Second Laser arrived, very consistant" and "Optotronics +150mW video" issued by Emc2, relevant to the laser you are asking for. It would be a good thing to go around using the "search" utility, as a lot of lasers have been already reviewed...
it arrived today and im ordering another one for my friend. my average output is 164mW average which is plenty of power to burn things, light matches, pop balloons... im sure u will be very happy with it.
just because it is a pen does not mean it is small, it has a nice feel in my hand and has enough weight. if you are not planing on burning anything just go with the 100mW version, but if you are like me go all out and buy the biggest one you can afford
welcome to the forum