(Can o worms)
My Thoughts:
1. The "Obama Sights" joke was a result of the fact that your sight completely covered some of the possible targets on the SEB when we moved back to 40 feet or so. If your front sight covers is larger than the target you want to hit, you are screwed. As we discussed, that is sniper pistol distance and not a likely defensive shooting situation.. particularly against a small target. And... I think I do recall someone noting that they hadn't shot at that distance with those sights yet after a miss or two.....
That said, the time you are MOST likely to need your sights is when you have extreme distance or a smaller target available.... so, choosing a large front dot that doesn't work well under those conditions makes no sense to me (even worse when you combine it with an imprecise rear sight design). The Large front dot sights were specifically put on pistols because of the assumption that you must see the front sight before you pull the trigger. I think that assumption is wrong. Keep in mind that I know the guy who started their use & the company that first made them... we're friends and we've had the conversations a few times.... He finds it humorous that I refer to his sights as "distracting".... I was trying to be nice.
2. "When should they be used?" That's an easy one: When you need them. How do you know that? Frequent and Realistic practice. There is no magic plausible defensive distance or target size. When you train, if you push yourself to use as little time/effort/energy as possible to get your hits, you'll figure out when you need them and when you don't. Please check out the Podcast on the topic of the "Balance of Speed & Precision" (recently linked in another thread in this forum) .
3. "What type Should be used?" Going back to item #1, keep in mind that your are most likely to NEED the sights with a smaller target and/or longer distances, so your sights should be designed for precision shooting. If your sights are designed to be seen quickly/easily/intuitively/whateverly at close distances when you probably don't need them, they are probably over-priced solutions to a problem imagined by target shooters claiming defensive context. The stock sights on most guns are Good to Go, as far as I am concerned. The caveat might be to upgrade plastic sights to metal ones for durability and reliability during extreme handling (such as racking the slide with the rear sight during one-handed reloads/malfunction clearing). I've seen a few Glock rear's ripped off, but honestly not very often compared to the number of times I've seen them abused (or abused them myself). The early M&P plastic sights broke easily, but I understand that the problem was addressed and haven't seen a front or rear break in over a year.
I'll be standing by for conventional wisdom, overused cliches, irrelevant claims of personal ability and (hopefully) some insightful thoughts....
-RJP