Mass production of goods, which made them cheaper for consumers to buy, is probably the greatest legacy of the Industrial Revolution. To put this in perspective, think of this: before the mechanization of spinning and weaving cotton, underwear were considered a luxury item only available to the wealthy.
One of the biggest differences the Industrial Revolution made was making people's lives more technologically based. Factories put a lot of people to work, and also produced technological goods for them to consume to make everyday lives better.
I'd say that the main achievement is that it built the foundation for the sort of world that we have now. The world became more industrialized, which led to the idea that machines can and should be made to make our lives easier. This idea has continued to grow and grow and machines have gone from just making clothes cheaper to giving us transportation to now giving us easy communications and entertainment.