I know that processors got faster and acquired special multimedia processing abilities and the companies began to push hardware abstraction layers that made hardware mixing obsolete, but it seems that Gravis Ultrasound for is the right spot for Dos when it comes to tracker modules like the .s3m module Second Reality for example
Do you guys agree on this one?
What is the point of this question? It's equivalent to saying "I know we have much faster cars these days, but in the 1800s people used horse-drawn carriage to move about, which was the optimal way of long-distance travel. Are horse carriages not used anymore?"
The Gravis Ultrasound was the right tool at the right time. It got made obsolete extremely quickly by technological progress. Its specifciations were great in 1992. Four years later already (maybe even earlier), its inability to mix 32 voices at 44 kHz and its memory layout issues for 16-bit samples were already considered to be a major bottleneck (just read the documents of contemporary trackers, e.g. Impulse Tracker's DRIVERS.TXT), and of course it was impossible to apply filters or other DSPs. The GUS isn't even the pinnacle of hardware mixing soundcards. The AWE32 was arguably the better sound card (with up to 28MB RAM, chorus, reverb and filters, and of course native OPL3 support), but even that was made obsolete quickly. So if your question is whether we agree that the GUS the best sound card of the DOS era, that's clearly a no from me. :P
So basically openmpt and xmplay is what's best to take it out from the dos era
Yes, for later systems, libopenmpt is likely one of the best options. Any GUS emulation will be massively inferior.