Had my S3.4's for just over 3 years now and still am amazed by them. I think they are probably permanent - even the wife loves them, which is a good sign! She has a better ear than I do anyway. Ha!
As for the tweeter, it still occasionally distracts me. Plus I am 6'6" so they tend to be a touch below my ear level. I seem to recall reading that this alignment was in having to do with room reflections, but I may be mistaken...?