I've never heard 'massive' used to mean 'great.' The meaning of 'massive' in UK slang that I am familiar with is to mean something like 'gang', 'crew' or 'group.' When I was at school some of the kids who liked to think they were tough called themselves the 'N-Town massive.' Cringeworthy, I know.

'brilliant' here in this comparison means 'great, splendid, distinguished , magnificent ' ... 'massive' and ' wicked' are used informally as slang to mean almost the same as great , awesome , excellent , very good ,amazing etc ... 'Wicked' as an adjective could mean 'very, really' The game was wicked cool !

Massive: this is a word meant to describe an object (or a person, if you must) that is HUGE (other words to describe it: large, very very big). It can also be used to describe amounts (of money or people, to give examples). Brilliant: this is a word meant to describe an idea or a person. An idea or a person can be brilliant. For example: "Albert Einstein was brilliant for creating new scientific theories!" (Other words: smart, genius, amazing, intelligent, astounding) Wicked: this is a slang word often used in the UK (British English) and parts of Australia. In general, it just means "very cool" or "amazing." For example: "That coaster at Disney Land is wicked!" Hope that I helped! ¡Un besito!

"Massive" means "very big", it can also mean something is large in scale or amount: There was a massive breakdown in communications. He has a massive forehead. "Brilliant" means "well thought", that an idea or persona is clever, smart, did something good: You're brilliant! The way you solved the problem, was just brilliant. "Brilliant" can also mean "shiny", "sparkling", "clear": I saw the brilliant sky. "Wicked" usually means evil, harmful, sinful: Those wicked friends of yours are up to something! He has some wicked habits. But it can also mean "great" depending on the context: Wow, this is such a wicked pool! All three can mean "great", but they also have other meanings.