I will little bit contribute with my sound experience 😀 I am a gamer, so I'm using the HW for good functionality and pleasure. My old machines are connected to Yamaha Z11 receiver with High-End Speakers, so when you play games you really hear the noise. Over the years I found few very good sound-cards that gives me pretty decent sound output. I'm not the guy who is comparing OPL3 vs Clones. i just want to play and enjoy the game experience and this is the list and pictures of the cards that I would like to recommend.
For Legacy DOS I recommend this two beauties:
Sond Blaster Pro 2 CT1600

(this is not my picture - I have the card in the computer so i downloaded the picture from the interner)
Roland SCC-1

with these two guys I have decent FM and great midi and mpu-401 controller. I have connected MT-32 to the SCC-1. I have to say that Dune on Mt-32 or Gabriel Knight on SCC-1 are really great music experience. Just love it 😉
For People who doesn't have any ISA motherboard but they still want to play DOS games I will recommend FM801 sound-card. This card has decent DOS drivers that emulate OPL3 pretty well and noise level is very good.
FM801

And if you are more into windows gaming and sometimes you want to play some DOS game, Diamond Monster Sound MX300 is your pick. The DOS drivers are so so, but it is possible to make it work and the sound quality in the windows is excellent.
Diamond Monster Sound MX300

I'm also using with Diamond XR385 daughter-board (yamaha DB60XG clone)
XR385

I have few other cards - few AWE32, SB16, SB16 Vibra, some ESS and SB AWE64 GOLD and Value editions.
All those are pretty noisy.
Please excuse my English.