You can output .WAV files with OctaMED Soundstudio and use .WAV samples as instruments as well. The added processing power of the A1200 will help a lot as will any added memory you put into it.
Modern PC music usually uses VSTi instruments that are expensive on editors like Renoise. Sample-based music is cheaper and doesn't sound much worse. If you already have a PC, you can use MilkyTracker to get similar sample-based results for free without needing a MIDI synthesizer.
One thing that is better on the PC than on the A1200 is that sound cards typically produce 16-bit CD-quality sound. The most that an A1200 can play back without a sound card of some sort is 14-bits. (Although it can produce 16 bits in software as a .WAV so you can burn it to a CD for better playback in OctaMED Soundstudio 1.03c .)
