I use step sequencer all the time, for mostly drum tracks. It has some quirks, but I have no trouble cruising through writing and playing with it.
If you or anyone else here, are having a bunch of issues with it, please detail each issue in a separate thread, so that we can try to help resolve the issues for you.
If Step Sequencer doesn't give you what you want, then there is also the Piano Roll View available, which though different, is quite powerful.
Thanks,
Bob Bone