i bought a 200 mw laser from megalaseruk and it didn't seem much brighter than the 95mw techlaser one i had at the time. it should have been noticeably brighter with a power of 200 mw, but i think a lot of that power is from IR and that 200 mw is only peak power. i honestly don't care for megalasers in my own personal experience. if u ask me... i'd rather pay 50 dollars more for a 95 mw true green with a higher duty cycle, tighter beam, and a true power output instead of a 200mw with loads of infrared. you could order from rayfoss or o-like when they are back up and running if they planning to come back >.< you can get a 200 mw for noticeably cheaper since you're not expecting a high grade IR filter on it anways. you can get a focusable hi capacity 18650 or pen versions with AAA.
that's just my opinion on the matter... although i've heard people not liking techlasers. their lasers seemed like a good quality one... at least the one i bought.
edit: i know you were talking about a 300mw laser, but i'm just talking about my experience. when applying that experience i doubt the 300mw is gonna be of any better quality. and this was like last year or so that i bought from them.
oh and if you read their blu ray product it just says they use a 1 watt diode. what kinda bs is that? it doesn't seem like they are very knowledgable in their laser builds... at least in my view.
They seem to last forever... >50000 hours