CTs are awesome. You set them up to put the dot just the tiniest bit over your front sight and it's like you have the greatest night sights on the planet. They not only glow, they backlight your front sight blade and illuminate your target slightly. You treat the gun the same as you would with no night sights and they just kick ass.
In unconventional shooting positions they're unbeatable.
Not that I'm specifically a huge Vickers fan but here's a good LAV quote: "There's some stuff you can do with lasers that you can't do without lasers. End of story."
The big downside: just like lights, they work both ways. Be quick.