I watched GOT for the first time through a couple years ago, and I just now realized how I would describe it -
It is somehow one of the most thrilling/entertaining/easily anticipated shows to watch as you make your first way through it. Yet, it's also one of the best 'background television' shows to put on after you've already seen it. It has stunning visuals, an exceptional soundtrack, and a healthy balance of action and intimate/compelling dialogue scenes.
Yes, you might have to google things as you go (especially if you aren't used to fantasy shows/movies) and yes, the ending disappointed the main fan base a bit, BUT....
if graphic & lewd scenes don't bother you, i HIGHLY recommend you make the leap and invest in watching it.