Green laser or red laser ??
Streamlight
Viridian 
Crimson
Lets hear it.

No experience with Crimson other than the grip laser.

I don't like the buttons on either the streamlight's or viridian's, but between the two, I find the streamlight has easier access to the buttons.

Green laser is my preference. You'll get better day and night vision with it, but whether or not it's worth the cost difference is completely up to you.

I had a Crimson Trace on a Sig 229 but it made the grips too large.

I have a TLR-2 on my Sig 226 for bedside . Laser is set for inside house distance.

TLR.

IMO, laser's are not as helpful as most hope. They often make people lazy and less accurate. I just use a TLR-1.

But, if you want a laser and will practice with it enough, to each his/her own

I have been looking at picking up a Viridian X5L-R which is the red laser version to go on my home defense M&P 9mm. I was looking at the TLR-4 but I like the Viridian's design better than the TLR because of how much more compact it is. I wrap my left index finger around the bottom of the triggerguard when I shoot so I think the X5L is a better option at least for me.

The X5L also has strobe functions with programmable speeds whereas the TLR's do not. As for the laser the only reason I want one is because the 3 dot on the sights get washed out in the light, even with night sights, and for shooting from the hip or if I can't bring the gun up to acquire proper eye/sight alignment I'll still be ok.

I agree though people can become handicapped by lasers and tend to think that the point of aim will be point of impact at most distances. It's more of a good general reference point of impact in my opinion.

I have a TLR-1s on the M&P9 FS.

i just put the X5L on my sr9. I have no other exp with lasers so i cant compare but i like this one cause of the small size and features such as strobe, my eyes are bad at close distances so i cant even focus on open sights anymore. took it to the range the other day bore sighted the laser to my open sights and was off a couple inches , got her dialed in and was hitting a 3inch dot at 20 yds with 90% of them in there. put some clays at 30 yds and nailed them everytime. got it on ebay for 159.00

Agreed, but I got the TLR-2 slightly used for a TLR-1 price.

I use a TLR-1 on my M&P9's

I run a SureFire X300 on my G35, and X200 (or X250) on my G20. I'm not a fan of the lasers. I prefer the sights.

this, night sights and an surefire X300 is all you need.

I have the tlr 2 and love it