For me it looks like 95% of renoise users have used older/other trackers before using Renoise. So is the market for Renoise quite limited or am I wrong?
first nope! i’m quite young so it would be quite hard to be part of it…
I got my Amiga 500 in 1988 and started tracking immediately. That was with Karsten Obarski’s “Ultimate Soundtracker”
That wasn’t 22 years ago, was it?? 
I started with OctaMED on Amiga 500.
Started with Octamed on the Amiga but we are talking when I was 12-14 years old so not anything approaching serious. Then had a long hiatus, got myself a PC many years later, played about with various music softwares and settled on Renoise when I felt it still fit me best.
Scream Tracker -> Impulse Tracker -> (holding out) -> (holding out) -> Impulse Tracker 3 still not released? -> (holding out) -> Renoise (where have you been all this time!!)
Somewhere in the middle I tried cakewalk and later Reason. I think I did okay with cakewalk and reason actually, but never really got into them. Before that I had used Acid for it’s timestretching ability, and somewhere in there used rubberduck for 303 lines.
Actually, it’s kind of fun to think of the old software that I used to use. I would switch back and forth a lot between Cooledit and soundforge as my audio editors. Off the top of my head I can’t think of any other software I used to use that often. I had a dos based soft synth that I tried but couldn’t make sound good. Then again, I can’t make current VST synth’s sound good when I try to program my own patches, so I can’t really blame the early software synth…
The best part of it back then was I could spend all the time I wanted and not feel guilty about it. Now I have way too many other things I have to take care of… can’t drain away the hours I used to spend on music.
1993 SoundTracker (Amiga)
1994 ProTracker (Amiga)
1996 FastTracker II
2000 Cubase
2004 Renoise
Also used Buzz, Skale, Impulse, OctaMed, GoatTracker and CyberTracker.
Started with Impulse Tracker in 1999, but quickly moved to ModPlug. I stopped being interested in composing music for quite a while, but at some point I tried Ableton Live and didn’t care for it. I found Renoise in 2007. I’ve been messing with it ever since.
ST3 -> FT2 + Velvet Studio -> Every free FT2 compatible tracker I could get my hands on -> Renoise ( + Happiness!)
sound tracker(on spectrum) > FT2 > Skale > RENOISE 
Well I am from that general era but I didn’t really use them that much. I tried most that I could get my hands on for the Atari ST(E), like Audio Sculpture, Protracker (all the different versions), Soundtracker, TCB, Musicmon and so on, but I was never really very serious about it. Also tried Notator and some other programs, but then I found Cubase (in 92-93) and I stayed with that up until I found Renoise a couple of years ago.
So I’m not really sure what to put my vote on here lol.
On the Amiga I just used trackers to listen to / look at tunes… 1997 I bought a PC and got FT2, so I started fooling around with that, but making something actually resembling music started with Renoise.
FastTracker 2 > Skale Tracker > Renoise
I only witnessed the tracker scene on its dying bed, where people were angry when somebody shared an mp3 instead of IT or XM…
“I don’t download mp3 because the filesize is so big and I can’t see your techniques!” LOL at that now!
Seriously Used: DMC 3 4 and 5 on C64, FT2, MPT and Renoise on PC aswell as Audiomulch and Ableton Live
Tried and used to some extent: Logic and Cubase
onboard Korg T3 sequencer (yay!) > cakewalk 2.0 > FTII > Renoise 1.11
Modplug tracker–>Magix Music maker (???)–>Fruityloops–>Ableton–>Renoise and consequent increase in productivity…
Got my hands on some tracker for pc in '96, can’t remember which.
Quickly found FTII and switched to that.
Went to Fruityloops after a couple years when I found the sound quality in FTII to be too limited, and FTIII didn’t seem to ever be coming.
Then to Nuendo after a while when I found programming in FL to be too limited.
Then I found Renoise 1.9
\o/
Started on FastTracker II, making terrible tracks after school.
Still using MilkyTracker on occasion.
i was raised by stereomaster and a tracker whose name i can’t remember on the atari st. but its only since discovering renoise that i have been attempting to input dna sequences myself.