I own Vetiver Bourbon and Macchia Mediterranea. Most of the ones from this line (labeled only as Monotheme but named the Classic Collection on the Mavive website) and the Flowers line are available here at low prices, less than $25/bottle.
They are pleasant, relatively simple, light fragrances, which smell good enough but aren't heavy hitters by any means. Most of them contain some citrus and floral notes which help keep them light and a bit fresh. Although they are not Eau de Colognes, they remind me of them in overall presentation. I have spent very little time with these, and I haven't worn either of them in about two years, so there's not much else I can say.
I've briefly tried several others, including Patchouly Leaves, Green Tea, White Tea, Agrumi di Sicilia, and Cashmere Wood, and they are in a similar vein. I haven't sampled any of the Flowers line.
My impression is that Monotheme is trying to make good value, attractively presented, decently constructed, light fragrances which have wide appeal, especially among customers who don't want to spend a lot of money on fragrances.