The SB has real OPL which is the only real advantage.

The ESS has a bug-free midi controller, a waveblaster header, much cleaner sound, 32-bit digital sound (ESSFM/WSS), and it's OPL sounds pretty good still.

If you aren't fussy, get the ESS.

Oh well free but 486 has no good parts it seems plain original "=time period correct 1992":
- some Cirrus Logic VLB card with only 1mb (2mb if full).

Wish I would find something worth noticing someday.

This thread has some good info:
Real CT1600 SBPro2 vs Compatibles? YMF ESS etc.

And if you want to check how genuine OPL3 sounds compared to ESFM see here:
OPL3 vs. ESFM vs. CQM vs. SBLive

The CT1600 is the gold standard for compatibility. When something is "SBPro2" compatible, that means it's written for the CT1600, so should always 'just work'.

Apart from that it's technically inferior on pretty much every count (noisy, unsubtle filter on everything over 11kHz, no MPU-401, no 16b sound etc), with only the OPL3 vs ESFM as possible benefit.

So: if you're hitting compatibility issues with the ESS1869-based card, it's worth considering. Otherwise not really unless you want it for collectors value.

I'd say a 486 with Cirrus Logic VLB based video is a good find!
Any VLB 486 is more desirable then a ISA only 486 and for some more then one with PCI
Depending which Cirrus Logic chip you have it also maybe one of the faster VLB options.
2MB would be nice, but not really needed on a 486 accept for the Windows desktop.

Personally I think the CT1600 is overhyped but it is desirable, so all up I'd say that 486 sounds pretty nice, and if it's free even better!