You get 16-bit sound sampling with a SB16, while the SBPro 2.0 is an 8-bit card. In practice, this doesn't make that much difference for DOS gaming, other than in some late-era titles like Crusader: No Remorse. On the flip side, the SBPro has a different low-pass filter which can make some older games sound nicer by making the output slightly smoother. The prime example of this would be "talkie" adventure games from the early '90s which used digitized voice recordings.

Additionally, the SB16 is not fully backward compatible with the SBPro, with regards to stereo support. This rarely comes into play though. Only a handful of games support SBPro stereo while not supporting the SB16 natively. There are other differences between various Sound Blaster cards, and most of them are documented in this Wikipedia article.

Lastly, there are a number of bugs which affect SB16 cards, but are not applicable to SBPro cards. You can read more about that in this thread: Sound Blaster 16 Bugs and Deficiencies Summary

doublebuffer wrote on 2023-07-18, 10:52:

What are the differences between the other cards, especially the difference between SB16 and SBPro2.0?

The most important difference is that SB16 (includes the AWE) do support 16-bit mixing and comes with an MPU-401 compatible interface, while the SBPro lacks both of them. Note that the advantage of 16-bit mixing in DOS comes to play with late games and multimedia software. The MPU-401 compatible interface isn't perfect, and several variants suffer from the infamous hanging-note bug. I recommend checking the link about the SB16 bugs and deficiency that Joseph_Joestar put for more info.

Another one is the low-pass filter implementation that the SBPro (most compatible clones lack this, though) has which is simple and works well with sample rates below 11 KHz. SB16 does have a brick-wall filter implementation that does a better job with higher sample rates instead.

EDIT: I just read that AWE is not SBPro compatible, what the..? I thought SBs are backwards compatible at least. Why would Creative design a card that isn't compatible with their own legacy cards and all the software which supported them, doesn't make any sense.

This is overstated and something that I wouldn't worry about it. There are very few games that supports the digitized stereo method of the SBPro but not the SB16 one.

Furthermore, the SBPro-compatible clones are more susceptible to getting the left and right channels swapped than the real thing.

Gmlb256 wrote on 2023-07-18, 14:07:

Another one is the low-pass filter implementation that the SBPro (most compatible clones lack this, though) has which is simple and works well with sample rates below 11 KHz.

From my testing, it seems that at least the OPTi 82C930 and the ESS AudioDrive 1868F have a functional low-pass filter in SBPro mode. It can't be turned off via software though, nor is it automatically disabled when higher sample rates are used.

The Yamaha YMF719E-S doesn't filter its output by default, but this can be solved through a hardware mod. After the card has been modified, the filter can be turned on/off via software and it also gets disabled automatically when high sample rates are used, i.e. just like on a real SBPro.

I don't have any Crystal based cards, so I can't speak for those. Also, I'm not sure if my Avance Logic ALS100 and CMI8330 had the low-pass filter or not. It's been a while since I used either card, and they are currently sitting in storage.

To make matters more complicated, there are two types of "Stereo" on SB Pro.
One is provided my using a real stereo PCM stream, the other by panning a mono stream to hard left/hard right using SB Pro mixer.

Last, but not least, SB Pro 1.0 uses two OPL2 chips, while SB Pro 2.0 uses an OPL3..