As stated in the article, it's not news that MVNO speeds are slower than their parents. And it's not surprising that the article failed to even mention Sprint and their MVNO's speeds, for that is a depressing subject---slow and slower, but cheap.
But---"Surprisingly, both Consumer Cellular and H2O earned a consistent quality score higher than what AT&T obtained: 72.8% vs 67% (Consumer Cellular vs AT&T) and 71.5% vs 67.1% (H2O vs AT&T)." I guess sometimes consistency is the hobgoblin of little MNVOs.
In fact, Hulu uses so much data per hour of video (1.5GB, because there's no setting to decrease video quality so it uses all it can get) that I can only tether through my Sprint phone if I first put it in 3G mode.
Otherwise Hulu burns through my 10GB of hotspot data in 6 TV episodes.
I can adjust video quality with Sling and Netflix but the Fire Stick app for Hulu no longer has that.
Bottom line is that I have to throttle my Sprint bandwidth in order to conserve hotspot data.
In addition to your good fortune to get 15 mbps from Sprint, and your misfortune in having to slide down to 3G due to the inability to set video quality on Hulu, it "seems" as if the more download speed I get, the more data is used than when performing the same task at a lower speed, which doesn't appear to make sense from my limited understanding of the physics of data use. Maybe I'm wrong, and the amount of data used during a task is equal regardless of different speeds used to perform it. That said, I have seen more than one person on Sprint's more expensive unlimited plans complain about only getting 2 or 3 mbps in most locations, and thus location may be everything with Sprint.
I think location is everything with all networks-- just more locations on AT&T & VZW on which everything else has a chance to matter.
In my region, I regularly see 15-19 mbps on Sprint, both on Sprint Postpaid (Unlimited BYP/free), and all the Sprint MVNO's I've tested (RingPlus, Ting, Tello.) FreedomPop Sprint is severely throttled, of course. I'm in a major metro area, and know that Sprint coverage can suffer badly in more rural locations.
Most tasks will use the same amount of data regardless of how much bandwidth is available.
In the case of streaming-- especially with Hulu-- it automatically adjusts the quality to match available bandwidth. I was getting insanely good quality video-- far more than I cared to get-- because there was lots of bandwidth available. By starving the bandwidth (going to 3G) it dropped the quality down from 1080 to 480 and used much less data for a one hour show.