I would choose Zemana Anti-Malware (or better yet, Anti-Logger) over Malwarebytes.
In my experience, Zemana was lighter on my system than Malwarebytes was. If I remember correctly, Zemana also uses multiple AV engines for its scans.
Zemana has a better detection rate than malwarebytes for sure, but even zemana has some pros and cons. If you don't already have an AV, I suggest choosing one to make it your main AV.
Zemana and Malwarebytes are both companion AVs and can work along side a main AV (even though malwarebytes has stated they are officially calling themselves an AV, their detection rate is still questionable)
I got 66 days left on 4 Malwarebytes Anti-Malware licenses. Currently, I don't even have it installed. Since they just had to fix what wasn't broken in the first place, I'll go for Zemana next time around.