Steven's singing. Operatic really. Huge range - very emotive. Very emotional and personal songwriter.
But also Ed's singing - more of an everyman's voice - much easier to sing, still very emotive. A lot of silly lyrics and wordplay from him.
the brief harmonies and featured songs from Jim (bass), Andy (keys/percussion til '95), and Kevin (keys post-'95)
Jim's killer melodic/harmonic basslines
Tyler's drumming is very straight, but extremely solid, dynamic, with great fills. It sounds simple, but there's a lot of hidden complexity.
Most songs tend to have a lot of structure, but aren't on the simplest side of pop, so besides verses and a chorus there's usually a bridge or even two. I like that this provides a tonal/mood shift in the songs.