I liked GoT's ending (mostly, I thought it was fine) and I liked Lost's ending (served the characters well, even if it forgot to address the mysteries, and got a bit too spiritual). Both shows had a ton of bad episodes, but never a bad "season." Saying a season is "bad" is unfair to the great episodes each season did have. I mean, Season 3 has arguably the lowest point for Lost (Jack's Tattoos!), but it also gave us that brilliant season finale and two of my favorite stand-alone episodes: Tricia Tanaka is Dead and Exposé (I know I stand alone in that assertion, but what a way to kill off unpopular characters, right??). And what of The Constant in season 4?? That episode alone is worth watching the three and a half seasons that precede it (and I'm definitely not alone in that assertion. See: any "top TV episodes of all time" list).
I mean, even this season of GoT had the great pre-battle of Winterfell episode, with so many fun character moments. It may not have lead to anything great, but as a standalone moment in the story of Game of Thrones, it was pretty nice.
All in all, I'd recommend both to any fan of TV. TV is more than how it ends or how each season plays out. It's about the episodes. These aren't 48-100-hour-long movies; they're a collection of episodes. If anything, the belief that TV is just a long movie (and thus requiring a "great" ending to be considered good) is what's ruining TV.
EDIT: Just wanted to add that I get that in this day and age of serialized TV, there is a lot of pressure put on the ending of a show (since there is some kind of overarching narrative) but I still believe that discounts too much the episodic nature of TV. Even if Barry ends poorly, we'll still have "ronny/lilly" and that will always be brilliant and I will accept no other answer.