Sense and Sesibility, for sure and I'm not just saying that to be different; I really do enjoy it more. I do love them both, but I love the characters in S&S and somehow it's more realisitic for me.
I like that it explores things that weren't talked about in those days, specifically Willoughby's behavior as a cad. The only other character like him is Henry Crawford (Mansfield Park) and even he didn't get anyone knocked up.
Another thing I love about the Jane Austen novels is how for the most part, by the end of the novels, every character has gotten his or her validation. In this case, when Elinor let Willoughby "explain" himself and how he really did/does love Marianne. You're not left hating him, but actually feeling sorry for him, and no longer feeling sorry for Marianne, but that she's really better off even though she suffered heartbreak.
I imagine that Elinor's machurity for her age (19) was not uncommon in those times, especially once losing a parent, which wouldn't have been uncommon either considering medical understanding was limited so people weren't living as long. I imagine that Marianne's lack of machurity was probably accurate as well considering Elinor was taking care of everything and trying to preserve the others' peace of mind by not sharing her own troubles, of money and love.
That dynamic is something people today can relate to- with all the divorcing parents, abusive parents, single parents, oldest children often feel, or simply without thinking do, suffer the brunt of the emotional, and sometimes physical, blows in order to shield the younger siblings from trauma and enable the younger kids to retain youth since they themselves have already lost it.
It's also a story for sisters, though, because it's not ALL tragic- Elinor and Marianne are best friends, but they still argue just like any other siblings. They are so close in age and they are the only two people in the world experiencing what they are experiencing together and they have a bond because of that. They are so different that they compliment each other- one plays piano and they other draws, so they are both artisitic, but in different ways.
Also, even though I think Edward Ferrars needs to man-up a bit, I am so happy for Elinor in the end that she gets her heart's desire. Another Austen trademark- every character gets his or her just desserts!