The TLR1 is not made by Insight like Streamlights first lights.
I carried the TLR1 for a while with no problems. I personally like the on/off switch on the back as the M3 was my first pistol mounted light. I like the ease of the momentary position. I switched to the X300 for a trial period and its smaller size just seem to let me manipulate the weapon a little easier (personal preference I guess). I still prefer the momentary switch of the TLR1 though…
I’ve seen the SF X200 fall off the SUREFIRE rail more times than I can remember. The adjustable locking rails loosen up. Don’t care for that light anyway - it’s neither fish nor fowl for handguns or carbines. Never saw a properly tightened TLR-1 fall off. Of course it should be checked before and after each range session.
I prefer the Insight M3X on a carbine for a lightweight light, and the 9-volt Millennium systems for a serious perimeter white light.
My wife has one on her Rock River M4 with remote backplate and she uses a foward grip with remote tape switch. She also has one on her XDM9 and she loves them. She has shot numerous hogs using her Rock River with the TLR-1 and it is pretty dang bright and for the price a great light. I have one that is on my Glock 22 and I like it, battery life is outstanding. For $90 it is a best light for the money out there (my opinion).
A properly installed X200/X300 has the screws loctited. However, the X200 was pretty anemic back when it came out and it isn’t even a contender today. X300 is the way to go, especially with a DG switch.
Dennis.
I’ve put 300 rounds through a XD45 mounted with a TLR-1 with no issues. It currently resides on the headboard on my wife’s side of the bed while a Spikes Tactical M4 leans against my side.
While I cannot report on the Surefire X Series of pistol lights, I can report on the TRL-1. I have had mine for 2 years now, and have put many hundreds of rounds through mine mounted on my M&P 9mm and my 1911. I have yet to have it work itself loose or come off. I use the same technique that I use on my Eotech 552. I get it finger tight and then use a penny or such to crank it down “about” 3/4 of a turn more.
I find that in a home defense role (and the distances I would need it for in my home) that it is suitably bright for my needs. Case in point. When I got it, I had my wife go down the hall to our bed room with the light (not mounted to a weapon) just before bed. I then turned off all the lights stood in the living room and told her to illuminate me when she thought I was coming down the hall. When she hit me with the light I had physical pain in my eyes. This was at about 20-25 feet. I then tried it with her, and she reported the same thing. She is a trooper.
I hope this small bit of info helps.
Adam
This seems like apples and oranges, or I’m just confused…
The G2L (let’s compare LED with LED) goes for $60-$70. The VTAC mount is $25, so you’re at $85 or $95. Given that the TLR-1 sells for under $100, it’s hard to see any cost advantage here.
Bimmer
Like many others have stated, I have a TLR-1 on my P220R when it’s on my night stand (comes off when I carry it IWB). No problems yet. 
As far as the whole G2 debate goes, I have a SF G2 with a SF KX4 head in a Vltor Scout Mount on my M16A4gery. Works pretty well, too.
I have had a TLR-1 and now use a TLR-1s. Solid and reliable for the money.
Haven’t had any issues with my TLR-1 mounted on a Glock 19. Easy to use, works, bright enough for indoor use.
I keep a TLR on my M&P and it hasn’t loosened up under fire.
There’s a link about modding the screw on a TLR for a carbine.
http://www.weaponevolution.com/forum/showthread.php?1578-TLR1-Thumb-Nut-Modification-Rev.-(A)
I downgraded from a TRL-2 to a TRL-1s (with strobe feature). The strobe version has a brighter output than the standard TLR-1 version. LAPoliceGear.com had them (TLR-1s) on sale the other week for $99.00.