I have been using the Shure 3cs for over a year. I have used the sponge as well as two different rubber inserts, though i havent special ordered the triple flange. I have found that the best sealing, hence bass production comes from the the sponges. in no case, even under heavy aerobic exertion with lots of sweat have the phones had any problems. The type of insert and size will determine the amount of ambient noise that you hear; and you should find that one of the multiple options meets your needs. I guess the combination of real solid sound quality, good fit, durability and fit options makes the shures a good buy.
good luck
good luck