For reference, I'm a 63-year-old straight male. I enjoy chick-flicks more than a lot of women do, it seems, and I enjoyed this one. I'm not sure if the folks who gave this under 5 stars simply have it out for Lindsay Lohan or were expecting something other than what the film wanted to be - a feel-good rom-com suited for all ages.
I know Ms. Lohan has gone through some difficult times, but I don't know that her acting was ever the problem, and I think her acting is quite good here. I found her character very appealing, as were all the characters really (well, maybe except for the author's mother, but the actress played that role well). I found the acting to be just fine across the board, and while the film wasn't a gut-buster, there were a few moments that made me laugh out loud. And the film was far less 'sappy' than many of its genre. Obviously the storyline wasn't realistic, but it also obviously wasn't supposed to be.
I've been to Ireland and the cinematography has me wanting to return.
If you're in the mood for something lite with attractive scenery and music as well as a decent storyline and performances (even if we all know what's coming), I think this will fit the bill nicely.