Ive used only a few resistance bands on normally the ones that come with different games for XBOX and Wii.  Bought 1 or 2 others from Sporting goods stores.  WHen I got these I was amazed how much better they are.  Very solid construction and durability.  Ive only had for a day but did a full workout using all the bands and I don't see any probs in the near future.  Will  of course update if so but..