Dyson.
I replaced soooo many vacuums over the years - they all broke in one way or another after about 3 years. I finally bought a Dyson (despite my husbands protestations over the cost) because it has a longer warranty than any other vacuum.
Read the warranty's. There is a reason Dyson costs more, and there is a reason it has a longer warranty.
Shark has a 1 year warranty.
Dyson has a 5 year warranty.