I'm way down below 200th on the SMB knowledge list. I've never caught one, I THINK I saw a couple when I was a kid. But I'm thinking about SMB in the future myself.
Say they don't spawn - heck, then you've got population control of your predators. The biggest negative I can see there is the fairly high cost to restock with large SMB (at least around here).
If you're not putting in bass until next year, that's lots of time to research, study, and contemplate SMB vs. LMB.