I am not a fan of combo and I wonder why people think of using such combos. I believe this causes a higher system impact than running a one suite would cause. Compatibility issues are expected when running such combos. I am not a security expert but other more advanced members might give their opinions.
It seems that you have misunderstood me. I was speaking in general that using combos pose a higher risk or incompatibilities and might cause a system impact. That's why I prefer to stay away of running combos.
SSFW and SAP Premium overlap. It's just going to result in double-alerts at best, and outright troublesome conflicts at worst.
SSFW is more than sufficient if you know how to operate it and have an understanding of malware behaviors. It will out-perform any AV or IS in the right hands.