I haven't tried Sandaraque and just added it to my 'to-test' list, but I have tried the other 2 and had strong reactions to both. I had very high expectations of Lann-Ael - on paper it sounds like a dream frag for me, but it was a major disappointment. I found it too sweet and cloying. A good cereal/bread note is something I'm always on the lookout for and Lann Ael smelled to my nose like a bowl of wildly sugared children's cereal that had sat too long in the milk. Definite negative from me.
Bois Farine was, however, a revelation in the opposite way - I wasn't expecting much and sampled on a whim and it is to this day one of the most unique frags I have ever sniffed. It really does have a non-sweet, floury note that is dry and wheaty and just wonderful.
Would love to hear other's thoughts on Lann Ael vs Bois Farine, for me it was absolutely no contest.