I can't comment on the Monsters, since I have never owned them but I have read those same stories too. As far as the Atrios, I have owned those and found the build quality to be very strong. Yes the housing is all plastic but it is a very thick and strong plastic. They also have good strain reliefs and look a lot better in person. I always thought the only way your are going to damage them was smash them with a hammer. They are also comfortable as the housing doesn't actually touch your ear when fitted properly.
The hardest part was finding tips I was satisfied with. The stock bi-flanges sound good but weren't all that comfortable to me. I recommend the new Earsonics bi-flanges. They are extremely easy on the ears and most importantly have a large sound hole to let more treble through. No modification necessary as they are made for the small bore nozzle of the SM3. The ES bi-flanges can only be bought direct from Earsonics at this time. I bought 2 pr to make the shipping to the US worthwhile. Good luck deciding! http://www.earsonics.com/osc/catalog/product_info.php?cPath=3&products_id=59&osCsid=7d920f04d9498ed7379f02866a1eda36