We have so many exchanges that have been around right from the early days and are still in operation, just as megastar mentioned a few of them needless for me to start mentioning then again but my focus in this comment is on the second aspect where you mentioned the longest and no trouble exchange ever in operation.

This will be hard to achieve, because most and all the existing exchanges all hard their share of various forms of attacks and abuses, They are strong enough to win over the troubles and continued operations which is why we may feel that all have been rosy for them from the start which is not so.