I have a Laserlyte K15. It's a bit pricey but I don't think it is any brighter than cheaper ones. Belt_fed has a Viridian (even more pricey) it is brighter than the K15 when we compared the two side by side during the middle of the day bright sunshine.
We tested a bunch of lasers for use on our tac weapons, among these were the Laserlyte and AimShot for the rifles. The AimShot 8100 series out did the laserlyte for price, brightness, dot size, and range visibility. I know some people don't like the AimShot product, especially its "four point alignment system", but its a decent and reliable laser for its class in both the red and green models of the LS8100 series.
The aimshot is easy to sight in once you get the hang of it and do it properly. Loosen all four set screws - SLIGHTLY - at first - about 1/8 turn, thats a mistake a lot of people make as they loosen them up too much to begin with. Then simply adjust left/right opposing screws for windage, and up/down opposing screws for elevation, as needed loosening and tightening opposites as adjustments are made. During adjustment you make small turns for adjustment, no more then 1/4 turn each time. Then a bit of loctite, and always finish final adjustment of a screw in a clockwise direction. As you adjust you do it until it just "snugs" then loosen the opposing side if more is needed and turn to "snug" again. One clue is, if the laser goes off during adjustment then you have the screws too loose as part of the power for the laser is through the case and its contacts with the screws. We subject them to 10 drops of 100 feet on to concrete, taken them off the rifles and put them back on (same spot), vibrated them, immersed them, banged on them, beat them on door ways and other objects, put 5000 rounds down range with them. Still worked and held zero. Once you get the adjustments done and the screws set (loctite) they simply stay.
The thing about a green laser being visible at a certain distance like 100 yards, you need to be a little careful about that when choosing. Is the dot visible by the shooter at the distance or is the dot visible at the target at distance? Both can be advertised as "visible at..." what ever the distance, legally. There is another thing to pay attention to also, read the specs carefully, if they start mentioning distances like 10 - 30 yards visible then what you really have is either a pistol laser or a CQB laser, if you have a rifle and want a long distance laser then those will not do you any good really beyond say about 40 yards because the dot size is going to start getting bigger beyond that and may be too big for precision work and may be too dim in daylight for any real good beyond those distances. Don't get hung up on green lasers either just because its green, for example, the AimShot LS 8100 red laser 1/2 inch dot is more visible and brighter in daylight then some of the more expensive green lasers in daylight. All green lasers are not equal even with the same power output rating.
Daylight tests: The AimShot dot was brighter then the LaserLyte at 100 yards, and was more distinguishable and usable for precison engagement.
Durability: The laserlytes broke on the first drop from 100 feet, all three of the ones tested, we got one more and abused it too but not dropping it this time, and it lost zero enough to where we were no longer on a man-sized target at 100 yards. The AimShot worked after each drop and round of abuse and held its zero and never stopped working thru all the tests.
Battery life: The laserlyte brightness got weaker as time on increased until the battery was dead. The AimShot held its brightness until about 30 minutes before the battery died at which time you could tell it was weaker but beside the laserlyte it was still a whole lot brighter and still usable where the laserlyte wasn't. Of course when the battery was dead on both it was dead.
Zero, visibility, and dot size tests were before abusing them, then tested again after for the aimshot but the laserlytes failed the drop test. Both the laserlyte and AimShot were visible with the naked eye at 50 to 70 yard range, the AimShot was brighter and the dot smaller and better for more precision engagement work.
Overall, the winner in the end for us was the AimShot due to the pricing and the dot size, plus it was pretty tough and took all the **** we threw at it. They did not look too pretty after we finished with them but they still worked. Although, one of them revealed a cracked lens a little later on when dissambled and examined. The AimShot uses a glass lens. The laserlyte is just too over priced for what you get, i'm not too happy about the way the laser is encased either nor the adjustment system as we found it just plain fickle for adjustment.
Yes, we tested others of like the BeamShot. The beamshot, well, it was ugly and the first one out of the package stopped working as soon as it was mounted, it leaked in the immersion, and the general abuse testing (banging on door ways, etc...those things that happen in tactical use) did it in too early, although one of them did keep working and held zero fine but the switch failed on it.
We mount two lasers on the M4's, a visible Aimshot LS8100 green and a modified AimShot LS8100 green laser modified for IR for night vision use.
