When rating sound and graphics cards, people often rate them for use in a MSDOS Time Machine. But... general midi was widespread around 1993. Windows 3.1 became widespread in 1993, and Windows 95 in 1995 (but was planned for a 1994 release, so most hardware companies would've assumed it'd be out by 1994 when developing hardware). I feel this ignores an important aspect of a sound card in particular -- Windows DOS Box and Windows game/multimedia app support. Windows-only games & multimedia apps are mostly rare, at least the pre-1997 ones, and are often reissues or CDROM releases of DOS games. Notable titles include Simcity Classic, Simcity 2000, SimTower, SimAnt, Civilzation, Lion King, Sonic 3, DOOM, DOOM II, Hexen, Civilization, MechWarrior 2, and Quake. But nonetheless, they are worth noting because they usually support MIDI very very well but support for OPL is sometimes poor. Their MIDI support is through Windows drivers, so all of them support the GUS series and AWE series.
More importantly perhaps, is that at least under Win95, most soundcards with a MIDI synthesizer, such as AWE series, can have DOS games, including DPMI protected mode games like DOOM, access this synth using port 330 as General MIDI, whether or not the sound card is General MIDI compliant. Considering that most bigname MIDI games run to some degree in a Win9x DOS Box (ultima series games tending to be a notable exception), this is a pretty key feature. It means if you do most of your gaming on Win95, GUS and AWE series cards should "just work" for MIDI. Faking DMA for sound blaster emulation, like for SB PCI cards or any non-Sound Blaster-compatible card, is also much easier in a Win9x DOS box than in plain DOS, so the support for DOS games with PCI cards tends to be quite good in a DOS box. This is important to consider, as by the time PCI sound cards were taking off, basically everyone avoided rebooting into MSDOS Mode unless they absolutely had to. Microsoft has a list on their website of games that do not run at all in MSDOS Boxes, and it's actually quite short relative to the total number of games tested. http://support.microsoft.com/kb/134400/en-us