As others have said, the Sprint 4G MiFi doesn't do well inside. The high mhz spectrum doesn't do well to penetrate walls. You very rarely get full bars inside in my experience.
It sounds good to try and use a 4G hotspot for your home internet, but once you start spreading out a single WiMax signal (less than 10mbps down, capped 1mbps up) to several people and/or devices, you're not going to be as comfortable as you would be with home cable internet.
Now, LTE might be another situation because the speeds are much higher than WiMax and it penetrates buildings better, but still you're relying on a wireless signal to come down and then be spread back out to the devices.
For people like me who play games, I don't see myself cutting the cable internet any time soon. Not to mention that I regularly use 75gb+ of internet every month. Don't think theres a single carrier (even Sprint) that would be okay with this.