I think Andrew is talking about the first one and not the latter.
And also this is not a very even comparison. Malwarebytes costs $24.95 per year for features X-Virus has for free. X-Virus is a "homemade" solution made by a few members while Malwarebytes has a gigantic user base and developers updating engine constantly.
In terms of blocking then it should varies but if we are going to base on maturity of product develop then its MBAM Antimalware however the potential product of Xvirus is continuously exist, it needs a through enhancement to improve more.
Malewarebytes. They have a good reputation and have a lot of good history. My school's IT uses them to clean infections when a teacher clicks a bad attachment and then bad things spread through the network infecting every machine. Always does the job