My own choice...
As with any electronics, I usually look at the limitations of the device to decide just how much it will limit my use of it. I do this with cameras and occasionally electronics. If the digital camera I am looking at has say a poor perfomance in lowlight or if it has a slow processing speed or even a low powered zoom, this can effect my work. I like both lasers suggested. The Hercules is a very solid build and therefore the size and weight are nice and intimidating to observers so they'll show more caution around it. It looks very nice in the pictures and appears to be machined from alluminium.
In this case, both devices appear well built. I personally can't stand all the safety features on the new laser designs (sometimes called 'Tard Features) because I like the beam to work the moment I press the button, not 2 seconds later after the delay safety kicks in and after I've had to employ the safety key. However, my old 20mW HeNe laser uses a key for safety so I'm used to some of these features. Both have a 100% duty-cycle. The 'shock resistance' and Waterproofing on the Spyder really appeals to me... a lot...knowing that dust and humidity is not likely to be an issue. They also claim there's no heat buildup due to the diode dissipation design although that's a pretty big claim so I'll have to get some feedback on this when others have tested them out.
*$1999 gets me a Wicked Spyder 300mW + Free 532nm Safety Glasses
(Average output 300mW/peak output 450mW) - 2x CR123a batteries
Dimentions (mm): 198 x 20
*$2389 gets me a Laserglow Hercules - 325 300mW-324mW
(Average output 300mW/peak output 324mW(?) - 3x D-Cell batteries
Dimentions (mm): 366 X 54
Now one thing stands out to me here and that's the batteries... Two D-Cells are VERY heavy accessories and the Hercules doesn't exactly fit in any of my pockets. The CR123a batteries in the Spyder will also work in my INOVA flashlights as well as my EOS 30e CanonSLR camera... and the Spyder does fit in most pockets although they probably would sit better in a slim nylon webbing belt pouch. But it's worth noting that a lot of rescue devices use CR123a batteries because they have a MUCH longer shelf life than others, including the THREE x D-Cell batteries that the Hercules series uses. It could be argued that the built-in forced-air cooling fan on the Hercules is another moving part which, should it fail to perform at any time, may render the device innert in some manner.
The Spyder also happens to ship with a pair of their new 532nm laser safety glasses (the ones that I reviewed last week) which have a wraparound 'Oakley' style to them. I think Laserglow should consider something along these lines for new purchasers.
So for me, the size, weight, battery life, waterproof/dustproof design of the Spyder with it's free set of $129 safety glasses is the appealing of the two for my needs although I could easily be tempted to go for the Hercules simply because of it's intimidating look. I just feel that all the visible safety features and the larger size draws a lot of unnecessary attention to the device if it's based on the GLP-III(?) design. Now the Hercules does come in another power: the Hercules - 350 (359mW-374mW) which sounds rather scary. It's getting pretty close to the power of a Class 4 laser too (Class 4 = >500mW+)
Assuming both items function as stated (I have used neither), I'd probably go for the Spyder myself. I don't think I'd turn down a Hercules but I prefer to carry smaller lasers when using portables. I tend to carry a couple of INOVAs with me (LED torches) so the smaller size and less weight would be welcome. And the Lithium CR123a batteries can sit in the device for months without running down.
