If laser sights work for you and you feel that they give you an advantage, by all means go for it.
Full disclosure: I've never used them.
Lasers definitely have their merits, accurate point shooting being one. My problem lies with the following: at both my LGS (indoor range) as well as the outdoor range just over the mountain, I see TONS of mall ninja/tacticool types. I'm sure you all see the same in some measure wherever you shoot. I've seen a lot of these guys shoot (marginally) well with their lasers, but can't shoot for crap without them. This worries me. Lasers take time to switch on, can fail, and all the other potential problems already mentioned by others. Train with Irons first, then practice with lasers. I really don't think that anybody involved in this discussion falls into this "mall ninja" category.
Our TFL users are by and large a careful, thoughtful, responsible bunch. But a large part of the bad taste in my mouth for lasers comes from this group. I hate seeing loudmouths tout their shooting skills when they're sorely lacking fundamentals.
That might be a character flaw of mine- I tend to let large groups of idiots ruin things for me.
I also see a lot of folks who are new shooters sporting laser sights. This one also worries me. Of course I can't fault them for wanting to learn to shoot, but I kind of want to go cover up the laser and say "practice without it first." IMHO, fundamentals (iron sights) should be learned and practiced, then pull out your lasers. I understand that not everyone has time and money to train all the time, so maybe a laser is a good tool for this crowd. But for me, it seems a little bit like buying your first gun and immediately having a trigger job done. Learn fundamentals first.
Again, I highly doubt any of those who have chimed in supporting lasers fall into the "new shooter" group, and could probably outshoot me blindfolded.