I’ve got Direct TV because my boat came with a KVH system and I get a good deal on their basic service because I’m an AT&T subscriber. It’s okay for basic TV, but if I didn’t have the equipment already I wouldn’t waste the money on it. The Direct TV content in their basic plan is marginal and the signal isn’t always reliable in bad weather.
In addition:
I sometimes use my iPad that is part of my unlimited data family plan. It connects to my boat TV’s with an Apple lightning AV adapter and HDMI cable.
I can either view content that I downloaded from Netflix and Amazon Prime if I’m Someplace with bad service, or I can stream things from both of those providers or most of the channels I have from my home FIOS account plus anything that I recorded on my FIOS DVR if I am someplace with good cell service.
I’ve got smart TV’s on the boat that have Netflix and Amazon Apps but they require WiFi and so far I haven’t been to a marina with a good enough WiFi signal.
I can also use the iPad for the internet, checking and sending emails, downloading the newspaper every day no matter where I am, storing all the manuals for the boat as pdf’s, streaming pandora, and since I’m a Sirius/XM subscriber in my car I can also stream music through their app on my ipad and listen to it through the boat stereo through either Bluetooth or one of the aux in connections.