When I was in Minneapolis (at IPR) doing a bit of Max/MSP teaching, I had a long conversation with a talented and insightful LA-based film/TV composer. We were talking about how we got into Max, and I mentioned that I bought it in 1995 (or so) with the plan of making the ultimate step sequencer. I was obsessed with step sequencers at the time, and couldn't find any software option that could help me.
I'm sure you are wondering why I didn't get me some hardware. Well, nothing new had come out in a while, and while I had a bunch of analog sequencers, they were expensive and not necessarily very flexible.
I bought the Max (and later MSP and Jitter) software, and slowly started working away. Over the years, I had probably have built 100 different step sequencer, and used them for creating a mass of music. It turned out to be a step that informed my whole career.
So, this composer asks me: "Did you find the perfect step sequencer?"
My response was not what he expected. The answer was: "Yes, it is a new sequencer for every use." Frankly, I never found a sequencer that was perfect for every use. But I did find that, by building a lot of reusable pieces that could be easily bolted together, I created a "sequencer toolbox" that could be used to create a custom device for each performance or recording situation that I faced. In doing this, I developed the perfect sequencer for me. I've used it under Wii control, under Manta control, for quickly creating creepy haunted house music and creating jumping dance tracks. This modular approach to step sequencing has also helped me understand the subtle nature of performance interface, and has helped me be a lot more thoughtful about software that I purchase for my own use.
YMMV, but this journey has contained some very valuable rewards.