Which would you prefer?
If you still want to download the complete first season, I recommend purchasing it from a legitimate source. Here are some file details for the first season: Under The Dome Season 1 Complete Download
Beyond the sci-fi hook, the show is a masterclass in social breakdown. Watching a small town run out of resources and turn on itself is what makes the complete first season so gripping. How to Get Under The Dome Season 1 Complete Which would you prefer
For the highest possible audio and video quality without worrying about internet speeds or expiring digital licenses, the set is the gold standard. It includes deleted scenes and "making-of" featurettes that you won't find in a standard digital download. Technical Specifications for the Best Experience Watching a small town run out of resources
If you are a physical collector, you can buy the Season 1 Blu-ray box set. Almost every modern box set includes a digital code card that allows you to download a to services like Ultraviolet (now migrated to Google Play/YouTube).