If you have Malwarebytes theres really no need for Spybot. Its pretty outdated and inefficient as a scanner. It was good at one point, and was decent competition for the old adaware se. Today its good for one thing, immunization. Spywareblaster does a better job of it though, but doesnt scan at all, just blacklists/blocks.
When I set up a computer it gets MSE, then I install Spyware blaster(manually update it once a month) then Malwarebytes. Always install Malwarebytes last, most times itll block Spywareblaster, Spybot, etc from blacklist/blocking certain holes. And of course, Adblock PLUS with whatever browser the customer uses. No one ever has an issue.
FWIW,
In the past I've had both Spyware Blaster and Spybot Search and Destroy installed at the same time. Since the main feature is passive blocking of malware there's no incompatibility issues. I've also run several different active anti-virus programs with no issues.
The one thing about both programs is since they're passive and they have no active detection feature (pop-up warnings) it's difficult to know if they do anything. If you keep them updated nothing ever loads and the scan feature in Spybot Search and Destroy will only detect the latest malware that wasn't previously blocked. It never detected anything new in all the years I used it but I've NEVER had an issue with malware either.