If you're in the city, any of the Mohu antennas work really well. Amazon has a few of the off-brands if you are looking to save money.
As a side note, I'm really thinking of dropping Vue and sticking to Sling. I absolutely hate the mobile restrictions Vue puts on you if your not on a WiFi network.
I will look at off brands as I only will be able to get 9 channels or so. I will see how Vue and Roku work and go from there....If for some reason I don't like I can always change.