I purchased the Fleur Mechanique when it was first launched in London and I quickly went through Un Gardenia La Nuit in a month or so. I loved it so much! As you said, the floral portraits are very realistic and induce calmness and tranquility. The throw of Un Gardenia La Nuit was a bit poor, but now Malle has just released an intense concentrated versions of most of the line, so I am planning on purchasing it soon. I also purchased Rubrim Lily and I think I love that even more. To me, it isn't really a lily but more of carnations; hot spicy, clove-laden yet fresh carnations. It's similar to JAR's Golconda and CDG Carnation. It's very powerful and has excellent throw. I did go through the entire bottle though. I'm really keen on trying the new Russian Nights (I think that's the name) and the new Coffee Society. I remember the rose being very pastel-like and childlike, the lily of the valley very true to the flower and the Saint des Saints candle being very similar to Serge Noire but with more sandalwood.
Have you tried their candles?