Yes, I saw both these movies. Let me start by saying that Friends with Benefits (starring Mila Kunis and Justin Timberlake) was FARRRRRR better than No Strings Attached (starring Natalie Portman and Ashton Kutcher). How can that be, you ask? Despite the fact that I find it VERY peculiar that both the stars from Black Swan ended up making very similar romantic comedies (can we say challenge?), the NSA duo just doesn't deliver the romantic comedy performance that FWB does.
Mila vs. Natalie
While there is no doubt that Natalie Portman is a great actress (proven by her roles in The Professional, V for Vendetta, Star Wars, and Black Swan), she is lacking in believability and comes off a little bratty in the movie , as Emma, the Doctor. While Mila seemed to have a better grasp and identity with her character and a more believable career as a headhunter. It is clear that years on That 70's Show, has given a Mila a bigger edge on Sarcastic comedy and she is much funnier than Natalie, although I don't know that Natalie was really trying to be. Mila wins!
Justin vs. Ashton
I want to naturally believe that Ashton is naturally more comedic than JT (who rose to fame as a member of N'Sync), but sometimes he just goes a bit over the top in NSA. This is where JT shines in this movie, he doesn't overact. This is the first moviethat I have seen JT in, where he fills the roll quite nicely (IMHO). In addition, I think that Ashton was poorly matched with Natalie, so that could have something to do with it. While there were a couple of parts in the movie that I thought he was supposed to be funny and didn't quite pull it off, Justin did a great job as a co-star and had a lot more chemistry with Mila than Ashton with Natalie. Justin Wins!
Overall, the supporting case in FWB was pretty awesome and included Emma Stone (whom I LOVE), Patricia Clarkson, Jenna Elfman, Woody, Richard Jenkins, Brian Greenberg (Made In America), Andy Samberg (I love you, man) and others. NSA's cast wasn't without highlights, it included Kevin Kline, Cary Elwes, Ludracris and Minda Kaling (The Office), among a couple others. Beyond that, the story line of FWB was MUCH better and intertwined (as much as it can be for this kind of movie). FWB wins!
Let's face it, Will Gluck kicked Ivan Reitman's but on this one. These movies aren't winning any performance awards any time soon, but I will tell you FWB was not a bad way to spend a Sunday afternoon. Watch both of them, I'm sure you'll be on my side.