This cordless model from Shark is a direct competitor to Dyson and has some solid features for the price.  It has equal run time and is lightweight, gets under lower furniture than the Dyson and costs less.  It's best feature is the roller which claims to not get hair wrapped around it and does seem to work much better than the Dyson in that respect. 
That being said the down sides are that it has no wall mount and has to be leaned against something to stand up, and does not perform nearly as well on rugs as the Dyson.  I have a very short pile rug as a door mat that this left considerable dirt and pet hair on and then my Dyson removed every trace.  If you have hard floors and don't mind the lack of wall mount and top heaviness this is a good buy and a good vacuum.  If you have a lot of rugs or carpet I'd spring for the Dyson.