Brilliant is what I want to put over my Disciple lipstick so that it looks more appealing on me with a touch of gloss on it. But also Brilliant stays on my lips for a very long time and doesn't leave me with any annoying 'my hair's all on my lips', 'there's a fly on my lips' stickiness at all. I prefer Illamasqua Brilliant to the clear MAC Lipglass most definitely, although I use the tinted MAC Lipglasses, because there's so much less stickiness even though the Brilliant stays on.
But I'd still rather use the Illamasqua Brilliant gloss instead of the cheaper brands of clear gloss out there because it stays on for so long yet again and feels so comfortable on compared to so many others. Plus I like the packaging for Illamasqua's lip glosses anyway, I find them very handy to apply.