Authentic st sound. Good use of "sidvoice" as shown on those systems. UI very tracker friendly.
cons: UI not very intuitive for those used to synth programs, strangers to its influence may even find it ugly ;)
Only one voice at at time.
There are alot of softsynths that try to emulate that video game sound, but this is probaly one of the most accurate. It may sound dry and limited, but it will accurate impose on you the limitations on old ym composers. The major problem is the fact that it is one voice, so it might be hard to get that cool multivoice robbing effect used in a lot of scene tunes. Program will not rpobaly be udpated, but as it is, it is a very stable effective chipish tool...
Gwem is a hard core scener that has done his research (to my ears it sounds as accurate as any of the atari emulators out there). The best feature is that it's free and does not require any kind of fancy installer. Hopefully if eneough people sned back feedback, he can try and code a three voice version.