Im a big shipper of RahLy bond, and adore Rahul and Aly both. But, personality wise, they are a lot different. Rahul is a few notches way above to Aly in his personality. Aly is loving towards his friends , but is manipulative and cunning in nature to everyone else. He tries to please everyone by being in the good books, which is a short term gain. It shows weakness in the character. Whereas, Rahul may b egoist and arrogant at times, but he's honest and straightforward, and has no fakeness in him. That's what wins the audience hearts.
Aly started fighting with Abhinav only after the push from Sallu and the audience questions. Otherwise, he was sweet to Rubinav on their face, even though he didn't like them. He knows Rubina is the most popular, that's why he never took on her directky.
Whereas, Rahul stood up for his self respect by locking horns with Jasmine and Rubina, the most popular faces of the colors. And he did this when he was a nobody in the show. Even a star like Ejaz was scared to give it back to these two ladies in the beginning. It's only Rahul who stood up agganist the bullies of the house, not caring about the game or their popularity. That kind of courage and conviction always wins audience hearts than game play.