I dont know much in detail about Mendelssohn. I guess it could be put this way: while Schubert was the classic Romantic, Mendelssohn was the Romantic Classicist. His orchestration and melodic styles/technique is generally Romantic, but he rarely steps too far out of the mold of Classical form, porportionality, and 'symmetry'. If you like fairly well balanced composers that are easy to listen to but also keep your interest, Mendelssohn is a good one. Although all composers have their own style, to me he is like a combination of Weber and Schubert, a 'masculine' style composer and a 'feminine' one, respectively.