What do you need it for? You can still get hardware sequencers but most of us (IMO) are on software these days - Cubase, Logic (back to Mac only AFAIK), n-Tracks, Ableton, Reaper, ProTools (midi is ok now).
I've used and like Cubase, n-Tracks. Reaper gets a lot of love on online forums. ProTools is still the industry standard for audio - but the more expensive versions with dedicated hardware - not the light versions - and MIDI is no longer fiddley.
Also I'm older than a lot of the posters on here - I see a fair number of the young gunslingers (who do live music performances) are on Ableton.
Hardware sequencers I've used (and found ok) were on keyboards. Best one I used was on a GEM S2 (by Generalmusic).
If you have access to a computer software is the way to go - and mix any backing to a stereo .wav or mp3 for playing along with live. If you need to make changes or manipulate the sounds/sections live - look into Ableton.
KVR is a good place to ask - lots of subscribers.
Good luck.
P.S. I'm over on the European side of the big pond. Steinberg's Cubase rules the roost - I heard there were a lot of Cakewalk users (or whatever it's called now) on the other side of the pond. No experience with it. Don't know what dominates in Asia - maybe a subscriber from there can chip in if you're out there and there's some fab software/hardware used a lot in that part of the world.