There are tactical applications for lasers where their use in daylight could be very beneficial. That said, and having used both red and green lasers in various environments ranging from bright daylight to very dark (new moon outside), I will say that I think green lasers have some advantages and some serious drawbacks.

Like any other tool, if the user understands the good and the bad, and makes an informed decision based on what they need the tool to do, then I'm all for it.

Here's my thoughts on red vs green lasers:

1. Neither is very visible in daylight. Green is very clearly "more" visible, but unless you are using it in a very shaded area, anything beyond ten to 15yds is extremely difficult to pick up.

2. Both work very well indoors and in low light, which is, in my opinion, the main "go time" for the laser. Green gives no advantage here and, in fact, the units I've seen and used can have some disadvantages. At close range, the green is much more likely to refract off airborn particles and "draw" a line back to the shooter...Not a big deal but if searching, as in law enforcement, or checking your house in a home-defense situation, this can be a disadvantage. Also, the green lasers I've seen and used tend to have a much larger and more pronounced "spill" to the laser beam, causing an almost spider-web effect around the dot. Red lasers can exhibit this if broken or dirty, but the green seems more susceptible.

3. Battery life...Green is generally lower.

4. Environmental Factors: Many green lasers have a narrower operating temperature range compared to red lasers. I've done testing in very hot conditions and got my green laser (Streamlight TLR-2) to shut down, but the light was so hot (sitting on the dashboard of a radio car on a law enforcement range attached to a "blue gun") that I couldn't hold on to it... I doubt a light would ever get that hot in a holster. I don't see this as a big factor but I do plan to do some cold-weather testing. It just hasn't been that cold here in CA...Even though I live in the mountains where it occasionally snows. I may have to do a freezer test or something.

Apparently higher-end "direct-drive" green lasers (or something like that...I forget the terminology) don't suffer from the temperature issue, or are at least less effected by it, but they are also more expensive.

5. Price. While it's hard to put a price on something that's possibly going to help save our lives or the lives of our families, the reality is we don't all have infinite funds. Given the various performance advantages and disadvantages, barring special use situations, I'd probably recommend the red laser as it works just as well as green in low light, doesn't have some of the (at least perceived) disadvantages, and is cheaper, allowing funds to be spread to training, ammo, etc....

As to lasers in general...I'm a big fan. I have several laser units and have owned multiple others on guns that I've since sold. I carried multiple laser-equipped handguns during my law enforcement career in the field and am aware of several shootings on my department where lasers were used with positive results. I have done extensive testing including various timed drills comparing the use of the laser and iron sights and have worked with multiple agencies, manufacturers, and trainers to develop an advanced laser training curriculum for my department. The key to lasers is the same key as any other tool...One must learn to use the tool correctly or expect less-than-ideal results. Training is imperative.