+ very bright center spot, brightest in short to intermediate range
+ very bright red laser, brightest in category
+ built like a tank
- very expensive
- heavy body
http://www.surefire.com/X400product
http://www.opticsplanet.net/surefire-x4 ... light.html
Surefire X300

Surefire X400

Streamlight TLR-2 - $225 - LED light source, 4.7 oz, 2.5 hr runtime, 135 Lumens, 160 Lumens w/ strobe function on "s" model, machined aluminum body
+ very bright peripheral light, center spot not quite as bright as X400
+ decent red laser
+ very affordable (not quite best but very good compared to price)
- heavy body
http://www.streamlight.com/product/product.aspx?pid=81
http://www.opticsplanet.net/streamlight ... laser.html
Streamlight TLR-2

Insight M6X - $300 - Xenon light source, 4.4 oz, 1 hr runtime, 125 Lumens, Polymer plastic body, water resistant up to 66 feet
+ brighter light at longer distances
- not as bright as TLR-2 at close to intermediate distances
- some say laser does not hold true after a few rounds
- short battery life
http://www.insighttechgear.com/products-m6x.htm
http://www.opticsplanet.net/insight-tec ... nator.html
Insight M6X

Viridian X5L - $315 - LED light source, 2.9 oz, 1 hr runtime, 100 Lumens, 140 Lumens w/ strobe function, polymer plastic & aerospace-grade aluminum body
+ green laser, easier to see in daytime
+ pulsing laser function
+ light weight body
- larger size (drops below trigger guard)
- green lasers burn up battery life 25% faster than red lasers
http://www.viridiangreenlaser.com/video/viridianx5l/
http://www.opticsplanet.net/viridian-gr ... 55786.html
Viridian X5L

Sig Sauer STL 900L - $190 - LED light source, 3.5 oz, 1.3 hrs runtime, 130 Lumens, same w/ strobe function, polymer housing w/ aluminum bezel
+ built in hex key wrench for laser adjustment
+ very affordable purchasing from BotachTactical.com for as long as they are still running the sale
- complicated controls (button layout)
- laser on function is independent from main on/off switch
- laser is placed behind lens, if dirty it can show a "ghost" laser
http://www.sigsauer.com/sigstore/showpr ... ductid=285
http://www.cheaperthandirt.com/53433-1.html
http://www.botachtactical.com/sigsasttali.html $95 - get an additional 15% off using keyword "stimulus"
Sig Sauer STL 900L

Insight X2L - $215 - tungsten halogen w/ xenon filled light source, 1.7 oz, 0.5 hr runtime, 40 Lumens, polymer plastic body, made specifically for sub-compact pistols
+ finally and option for subcompact pistols
- very expensive for size (needs competition to bring down price)
- only fits on sub-compact pistols (does not fit on FN FiveseveN)
http://www.insighttechgear.com/products-x2l.htm
http://www.opticsplanet.net/insight-tec ... light.html

Glock GTL 21 - $250 - Xenon light source, 3.2 oz, 1.2 hr runtime, ? Lumens (was not advertised), polymer plastic body, water resistant up to 33 feet
+ nice compact design
- battery door can easily come undone
- bulb could become unseated
http://www.glock.com/english/acc_gtl21.htm
http://www.cheaperthandirt.com/18273-1.html

HellFighter Underboss DOH 202/203 - $125 - Halogen/LED light source, 3.2 oz, ? Runtime(not advertised), 150 Lumens Halogen/120 Lumens LED, Aramid fiber composite body
- battery door can easily come undone
- bulb could become unseated
- laser does not hold true
http://www.opticsplanet.net/dark-ops-he ... light.html
http://www.hellfireusa.com/cgistore/sto ... 11291.4992
HellFighter Underboss DOH 202

After review, strictly on paper from other reviews, the Streamlight TLR-2 would come out on top. Just for the price compared to the quality received. As far as best product, the Surefire X400 in my opinion wins gold. If best is what your looking for, at double the price, the X400 would be the way to go. The X400 is well built in every way and thats how Surefire likes to build their products. The Viridian X5L is a nice option if you prefer the green laser for use in daylight hours. However, green lasers lose battery life much faster as compared to red lasers. If this can be fixed, Viridian could possibly pose as top light in this category. The green light does seem to be easier to see, especially at longer distances.
All pricing was used from opticsplanet.com. They seemed to be consistently on par with a low price, if wasn't available, found an average low price.
Also keep in mind, I have never had any of these lights in my hands ever. These comments are strictly from other posts from this website, manufacturer's website, and other forums/review sites.