Eh, it's a matter of taste. I'm actually much more partial to Zack, but I don't really write for FFVII anymore so it doesn't really matter either way. XD

Still, there are bigger things in the way of Cloud/Aerith than Tifa. Unless, you know, Tifa brought Aerith back to life and is keeping her all to herself. Which, while a pleasing mental image, isn't exactly the most likely of plot points.