it depends on the actual laser you recieve, the beam specs can be all over the place with cheapies (although most are still a decent beam, just not "impeccable" like the LG and Opto offerings - then again, they are a fraction of the price) ....
Any single CR2 or CR123 laser is generally going to have a short battery life if it's putting out 150mW, the average CR2 is 400-500maH, and considering you are likely pushing a minimum of 1/2W pump to create 150mW of output, the battery would be to zero in about 40 minutes - realistic runtime at full power will be much shorter (I have a green module that puts out 173mW peak and I have to recharge it every night after I use it at the shows, and it probably really only is on 15-20 min total all night)
Keep in mind that alot of these low-buck lasers can't take the 3.6v versions of the CR2/123 and people insist (far too often) on running them in their lasers, that explains at least a percentage of the failures we're seeing, IMHO.
Hope this helped - I still wouldn't steer you away from that 150 if $ is an issue, just if you have some (OK, a LOT) more $$ the LG and Opto lasers are definitely more of an investment than a "purchase" (I hope that made sense)