I agree with docbrown here its definetely nothing too special, a more last-resort type thing. The things I remember most were the god-awful taste and associated burps, the weird nose-stinging effect and the marked disorientation I got from it (which was kind of fun). Most times (oral doses around 150-300mg) would give a low level buzz akin to like a low dose phenobarbital buzz, but thats a loose comparison. It is also sort of like barbs in that you tend to forget about the effects if you're not focusing on them or doing anything. Sitting around on clomethiazole I did not feel it at all. Standing up, walking around and doing some cooking I felt it a whole lot more.
I noticed more pronounced effects when I dissolved it in water (which took a while) and shot it back like vodka. Tasted god awful, no burps though compared to capping it, and it came on quite fast though it seemed to have a shorter duration if thats possible. Its pretty "glow" inducing but honestly other than that its not too special.
My most notable experience was 200mg with 1.25mg clonazepam while very stoned. I got extremely pleasurably disoriented and a buzz out of this world. That being said, that was a combo, and clomethiazole is pretty fuckin risky with combos, especially with other depressants.