100mW to 1000mW....?

Sirius Optics (
www.sirius-optics.com.au/laser%20pointer.htm) are selling 20 and 30mW Green Laser Pointers. Are these not bright enough to do the job?
I have not looked into green laser pointers yet. Some of the BAS club members use them as finders and to point objects out to the public. After being asked many times where in the sky the scope is pointing, I have started to toy with the idea of buying a GLP as well.