Allston is good when he's writing X-Wing and focusing on writing Wedge, Janson, Hobbie and his own characters. I haven't enjoyed his work in FOTJ or LOTF though alot of that might because I don't like the direction those series have took. Also he sometimes struggles with characterizations of other writers creations, namely Corran Horn as an example. Though to be fair Corran is always at his best when Stackpole's writing him though Zahn has a great grasp of him as well.