Not really a best, it depends on what type of coverage you have in your area.
I have terrible data speeds in my home for Sprint service. I have excellent data speeds for Verizon Service, I have good speed for ATT service. You have to try out the providers to see what is best.
I currently use Solavei. I only pay $49 plus tax and I left Verizon to try Sprint, to try ATT, to T-Mo, and finally settled on Solavei, because it is all you can eat, and the service is affordable and the coverage works good, not great in my area, but for the price I can't complain. I get about 6Mbps download, and 2 upload. That is good enough for what I use my phone for. Check them out if you can, but with anybody always make sure you have good acceptable coverage where you live. www.solavei.com/jsimple