Ezra Fitz: Ezra has been with Aria since the very beginning, before Ali's body was even found, before he was her English teacher, before Hanna, Emily, and Spencer were even on the screen, we met Ezra. Although their relationship was technically forbidden, Ezra managed to get a new job so he can be with Aria. He does have a crazy, jealous ex, Jackie, and he currently teaches at Hollis. Ezra truly cares about Aria, even after Aria tells him the truth about The Jenna Thing. Ezra would never do anything to hurt Aria, even though he once "lied" about the Jackie thing by nottelling Aria of her existence, as Jacki was once engaged to him.
Jason DiLaurentis: Ali's older brother who just recently returned to Rosewood, meaning him and Aria have no history (love-wise, anyway) but all of a sudden, Jason and Aria are "interested" in each other. Aria, although she refuses to admit it, is beginning to have recurring dreams about her and Jason together, and Jason actually admits to Aria his feelings for her, and then kisses her. Aria then leaves, knowing she still loves Ezra. Jason is actually spying on Aria, most likely setting up cameras in her bedroom, because he has pictures of Aria sleeping locked up in his shed. Jason and Aria may be cute together, but he is definitely a creepy stalker. Plus, he's still a suspect, for both Alison's killer and also A.
I definitely think Aria should choose Ezra. Ezra, like I mentioned, has been with Aria since the beginning, unlike creepy Jason, who can't be trusted.
Aria's dream about Jason