HUMM..... oh yea..... first of all, 250 is over twice the energy of the 100, but the 250 Herc will actually be much higher for the first several minutes.... so you will notice a pretty good difference.
I too have the DL 125 and its awesome for a little guy, but my Herc 300 does put it to shame.... of course its much bigger too... but I would say its at least twice as bright and the beam will "look" bigger due to the extra brightness... similiar to how the dot looks bigger when its on a white object verses a dark.. the dot didnt' change, but the eyes perception did....., so with that into account you could say maybe 3 times more dramatic to the eye using the Herc.
And if you put the dot on your skin?...... you will think 10 times more dramatic!
My Dragon will pop a balloon at 10 feet, but my Herc will do 25 feet.. but at 25 feet the dot is quite a bit bigger than the dragon at 10...hence the dramatic effects on the eye as the brighter beam "and" more width takes its toll.
The Divergence on my Herc is 1.1, but any laser will get big with distance... the question is... how bright will it still be?