I can beat that slightly, having started on a Commodore SX (one of the first affordable portable computers) running Dr. T's..! But after ditching the Commodore, and struggling with built-ins for a year or two (and yes, AYPN, you can do some decent work all in the box if you choose), I got an Atari Mega4, and Cubase. Been with Cubase ever since. It might miss a couple of things from Logic (and Logic misses a couple of things from it!) but familiarity with the tool trumps outright capability when you are trying to sequence fast...

I see where you are coming from now, AYPN. Yes, while you are in the infancy of doing this stuff, it is often easier to stick to a more limited tool, and just concentrate on the music and not the technology. But as you grow, eventually you bring yourself up against those walls that the hardware sequencer puts up. I too have a Kurzweil, and often find myself routing arranger parts into that for sample replacement (or going to some VSTi's). It's at this point I REALLY find the power of the software DAW/sequencer to be of use, because it is rare to find a part that works OOTB on a substitute sample.

For me, a combination of arranger sequencer then computer for polishing gets the job done quickly. Just find a good sequencer and stick to it. Eventually, it gets like playing an instrument. You don't have to think, the tools and techniques just come naturally. Practice, practice, practice!