What are you wanting to sequence? Drums? Synths?
I had a lot of success with OT MK2 sequencing drum racks in Ableton Live for a period of time before I went out and bought three more drum machines. 
And I think it is solid for sequencing soft synths as well.
Things like LFO designer, trig conditions/fills, and the MIDI ARP all help in making it fully featured.