The TR-808 is up there with samplers and the Amen Break in terms of defining modern music. If you have twenty minutes, there's a wonderful video explaining the Amen Break that I suggest everybody watch at least once:
IMO Amen was much more fleeting than the 808. Can't remember the last time I heard Amen in a mainstream track. Amen is super gritty and compressed which limits its style. 808 is an instrument, much more malleable.
https://www.youtube.com/watch?v=5SaFTm2bcac