Depending on the CRT you're driving, you might get slightly higher quality output from the new Direct Video analog system. You buy an HDMI->VGA converter with a specific chipset, and configure the ini to use Direct Video. That changes the digital HDMI output to analog. It's best suited for VGA-type monitors, and will show more colors and will generally have a slightly superior signal on that type of device.
However, it's not as compatible with TVs as the analog board is, and you can't do both digital and analog at once, as you presently can with your setup. You have to pick one or the other.
As a very minor benefit, you could then replace the analog board with a digital one, which would in turn allow you to use dual SDRAM sticks. That's not very useful right now, but it may be for the Saturn core, if that ever gets into a releasable state.
If you want the Direct Video thing, AFAIK you can do that without removing the existing analog board. It might even work with both analog ports at once, although I don't actually know that for sure. If you move your CRT to the HDMI->VGA conversion port, you can leave the I/O attached for the buttons and TOSLink. Then, if the Saturn core ends up needing it, you'll have the option of swapping in a digital I/O and a second SDRAM stick.
edit: from the other comments, I guess the user port/SNAC is also new to more recent I/O boards. If you're interested in lightguns or an MT32-Pi, a new I/O board would support those. If you just want retro controllers, the USB Daemonbite adapters are easier and just about as good; they have about 1ms of lag compared to SNAC. You wouldn't likely notice the difference.
