I'm hardly the most well-read sci-fi/fantasy reader, but Elantris feels less realistic to me. If I were reading the two books without knowing anything about the actual chronology of publication, I would have immediately said Elantris felt much more like a first book than Warbreaker did. (In fact Elantris is a first book, and Warbreaker's a much more recent one.) The characters in Elantris are more unidimensional, the magical system is somewhat less complex (perhaps disputably), and so on. So if you're looking for a richer story and characters, Warbreaker is better. But both are still good entertainment regardless: Warbreaker is just more complex and more fulfilling. I don't see an order as necessary for reading them, although I'd probably rather build up from good to better, personally, so I'd say start with Elantris and move to Warbreaker.
The Mistborn trilogy's also worth reading if you have time. And last, I have The Way of Kings on my shelf waiting to be read, but I haven't started it yet.
Regarding style, do note that the style of The Gathering Storm and Towers of Midnight are a hybrid of Jordan's and Sanderson's styles. Once you get into either book you lose yourself in the story quite readily and forget that it's a mixture of two styles, so don't worry about Sanderson overpowering Jordan. That said, sometimes it's "obvious" (although Sanderson has said guesses about who wrote what are sometimes completely wrong) that an action-heavy, dialogue-heavy section is just too fast-paced and punchy to be anyone but Sanderson. And that's a good thing! While I'd prefer just a touch more of Jordan's deliberateness in the books, I much appreciate knowing there are no fifty-page bath scenes to get through, and that development never really slows throughout each book. :-) It's also nice to get books with only around a year's lag in between. Sanderson's a machine compared to Jordan.