Marcus Canty is more Bobby Brown than Chris Brown.
I'd say Marcus Collins has a better tone to his voice. The rich quality which shows through when he uses vibrato on a sustained note. He catches the groove of a song better, but he's possibly less of an interpretative singer - I checked out some of his performances going back 5 years at YouTube and he hasn't changed a single thing in how he sings Signed, Sealed, Delivered, for example. He sings a song 'straight' and rarely vocalises around a lyric. He can bop about, has better than average performing skills, and is good looking. I'll score him 8 out of 10.
Marcus Canty (MarcUSA?) doesn't have the same tone, but is more of an old skool 'soul' singer, and has a better vocalising ability. His runs seem haphazard at first, but somehow he always manages to end them well enough. He's also a good looking diminutive guy, puts on a performance each week, and is a much better dancer, even sexy with it - I particularly liked that hip hop/Cossack dancing he did early on, 'Canty Pants' I called him. I'll score him 8.5 out of 10.