5x vs 10x BE's and relative beam brightness

I'm debating on going with either a 5x or a 10x BE for my 300mw 532nm hand held. The main concern is the beam brightness when viewed from the side. Anyone that has seen 532nm beams through varying BE sizes.. how did it effect the beam brightness? Was the 10x beam very noticeably dimmer than the 5x when viewed from the side?

The power density will be a fourth, so perceived brightness would be about half.

Application?

That's what I was looking for. It seems so basic of a question that I wasn't sure if the answer would be really that simple.

Would the beam through a 10x be half the brightness of that through a 5x?

The application is simply for visual effects and fun. I really want a thick, meaty beam.. but want to maintain as much of the brightness as possible.