These two movies came out right around the same time...they have different actors in them, but they're the same movie. I've seen both and enjoyed both. Niether ending surprised me, but it was the journey I enjoyed. I liked Friends With Benefits more though because Mila Kunis is awesome. See for yourself:
Now if you combined the two movies taking the male character from No Strings Attached with the female from Friends with Benefits you have the real life story of Ashton Kutcher and Mila Kunis. The two claimed they were just friends, but now they're not shy about their PDA.
Ashton and Mila Tom Mienelt/Splash News
I actually really like these two together they seem so natural and maybe it's because they were so great as Jackie and Kelso on That 70s Show. Mila has even talked about marrying Ashton. We'll see if he jumps on that idea now that Mila Kunis has been named the Sexiest Woman Alive by Esquire magazine.
Sexiest Woman Alive video...CAUTION THIS VIDEO IS HOTTTTT!