I use directTV with a KVH sat dish. The company paid for the dish, and the crew pays 145 a month for satellite TV. If you use internet, your local provider has stand alone modems that provide coverage for the boat. You could even network off that to wifi to your phones.
On my personal boat If I can't find it on my phone, I don't need it. And I removed the TV cable, and tv stand. I am trying to get AWAY from this crap on TV (if only for a while) On the occasion that I do need internet, my phone acts as a wifi hotspot. But that is very infrequently.
Regarding how 'good'? Any satellite is direct linked to a satellite in view. If you're in a wooded area, trees, leaves, or obstructions any satellite is degraded. Even at sea the satellite is subject to heavy rain or sleet, snow. If you're tied to a dock with a visual obstruction to the southwest, then you'll be lucky to get steady satellite also.