I just upgraded to a "domestic unlimited plus" plan from AT&T so I could use my iphone as personal hotspot for my mac laptop. For 48 hours it has been working well enough, on West End south of F'sted town near Sandcastles on the Beach and Cottages by the Sea. Sometimes I need to fiddle with it a minute or two to get the connection between iphone and laptop working for a new session ... such as switch hotspot on and off to reset, and/or tether iphone and laptop together with USB cable instead of Bluetooth or WIFI. I have been watching hour+ long lectures presented as video or audio. I use the audio option to minimize occasional download interruptions.
In short, it's been a bit slow but good enough for my single use, a few hours a day. The benefit of not acquiring and carrying yet another device, having portability including while traveling, instant on/off service without activation fees, and other conveniences is satisfactory compensation for the slow connection. And I don't trust that the other option speeds are necessarily better.
Good luck. Would be curious what you decide and how well it works out.