I openly admit that I don't have enough data on non-Swedish Mormons. From my point of view, growing up in an area where attempts at conversion were at least two a day, the ones we did have were a welcome change and the ones we had most definitely came off as less aggressive than similarly fringy churches.
I should also point out that I'm a bit of a pragmatist. To me impact trumps outlandishness, which is why I need more data on impact before making my mind up.
Sweden separated chuch and state first in 2000, so like anyone born before that I was born into the Swedish State Church which is Lutheran Protestant. I was even baptized (at 3 months) by parents who, despite being atheist themselves, found the tradition quaint and beautiful. I got to choose whether I wanted confirmation at 15 and chose not to be confirmed, but to this day I remain a member of Church of Sweden which basically means that whenever I am taxed in Sweden I pay tithe to it. I have looked into what that money, mainly, goes to and I mainly approve, so I keep paying. Do I like what the church stands for on a "spiritual" level? No. Do I like what they do with the money I pay them? Mainly, yes. I have seen the impact a CoS youth center can have on a disenfranchised area - but I have also seen my own father be encouraged to talk to the parish priest about his alcoholism instead of seeking medical and psychiatric help. Of that, I don't approve. CoS - good if you are young and underprivileged, bad if you are a middle aged alcoholic who really should be in treatment... But overall, the impact is mainly for the good. CoS rarely sticks their nose into legislation. Their official stance was against the synod that tried to oust women priests and they have a number of female bishops.
Their most problematic stance is regarding homosexuality. CoS practices a kind of "silent disapproval". Doctrine is "love the sinner, hate the sin" which, to my mind, is wrong because I can't see how homosexuality could be a sin. (I can't see how anything that personal or with such low practical impact on anyone else can be a sin.) So I disapprove of their disapproval. However: do I find that CoS goes out into the communitay and actively discourage people from homosexual actions? No, not in my experience. The problem starts when a homosexual person is also a believer. That's when the hurt starts and I don't approve. If the church does not mend its ways regarding this (and mind you, this is partly depending on individual vicars and parishes) I may still consider leaving it and withhold my tithe, despite the good work that they do.
And issues like this is what I'm looking for when I say I need data. To me, all major religions make incredibly outlandish claims. To make my mind up, impact is where it's at.
And of course, as with any religion, an important secondary endpoint is "Treatment of Lapsed members".
If I understand the "how long it's been around" argument correctly, it's not a matter of chronology but that when we have recorded history to measure against, we can know for a fact some claims are bunkum, while we have to strongly suspect claims made in, for example, OT, are bunkum.
Usually, to the inquiring mind, "We know this is false" trumps "We highly suspect this is false". Which is why it is considered slightly more odd to choose to believe something known to be false, than something highly suspected to be false.
But I don't find it as easy as that: while, for example, it is highly likely that a convicted fraudster is pulling a fast one this time too, we can't actually know that. If we don't believe in god, we don't believe god spoke to anyone, no matter their rap sheet. If we hold it possible that someone is spoken to by god, then there is no reason for god not to choose a convicted fraudster. I.e. Moses, Muhammed, Jesus, Robbard and Smith are about as plausible anyway. The difference is so marginal, that I personally can't call it on that. (No. I personally don't find even Xenu any less plausible than burning bushes or surviving without food or water for forty days. Call me crazy.)
I will have to call it on impact and on the behaviour of the adherents, because all the claims are silly to me.
I will voraciously read any post providing insight to impact. Like the poster above who felt angry and slighted when the Mormon kids couldn't play with him as a child. That kind of behaviour is silly and counts against. Providing charity is not silly and counts for. Proselytizing is silly and counts against. Standing by a principle of anti-violence, but still contributing by taking risky placements as medical staff is not silly and counts for. etc.
Until I was about in 4th grade I had no idea of the differences in the Mormon churches and just told my friends I was a Mormon (not inaccurate, but not what they assumed I meant). I found out rather harshly one day that I was a 'rebel', and went through a rather fast ostracizing with some of my long time friends who were Mormons of the Utah persuasion. They'd had some kind of lesson on RLDS and realized before I did that we were different. I went through angry, and hurt, confused, and finally resigned. RLDS for it's part, did a pretty good job teaching me about how wrong LDS were about everyting. 
