I used SecureAPlus for around a week, and it was just constanly doing a universal scan. Im not exaggerating, it was constantly doing scans. This caused me major slowdowns. For this reason I chose Zemana.
Zemana AM for it's lightweight qualities, SAP relies more on whitelisting objects and initial scan can take a few hours. However for offline protection SAP's lockdown mode can be useful.You can also choose the engines but ZAM does the job effectively too on less memory.
Zemana for me. It is featherlight, scans very fast and has a great detection ratio. The only downside are the FP's, but compared to some time ago, it seems that they are gradually working on this, which is nice. Overall a great product to have.