I really enjoyed it myself. But it is very dark. The acting was really really good especially the stalker male lead. I think I also just enjoyed that the female lead was smart and did the right sensible things. I wrote a review about it already on here and do recommend it but it is a subject matter that isn't for everyone depending on personal triggers.
I would say the difference between the two from what I can tell is that one is a mostly innocent woman (although she is having an affair with a married man) being stalked by someone she didn't encourage. But I found the psychology in this one very interesting for his back story and it does a great job of portraying his mind frame and how he views everything too. Its very sad in places too.
The latter is a man who is stalked by the woman he has had an affair with so there is a different dynamic there. I haven't seen it but I'm going to assume it's very bunny boiler, fatal attraction from the screen shots I have seen.