I have used it. Clomid pretty much caused a complete mental break down on only 50mg and didn't make me ovulate, so no doctor will let me get near it again - not that I'd be inclined to try it again, anyway!

You take it for five days at the start of the cycle. I found for those five days I'd have a few hot flushes, but that and some headaches were about all the side effects I ever had. I ovulated beautifully on it every single time, with a perfect luteal phase... Those FETs were not successful (well, 3 from 4 were positive, but miscarried) but I strongly believe that was down to embryo quality as I was quite severely hyperstimulated when producing those embryos.

Long-term clomid use can have a few detrimental effects - thining lining, reducing cervical mucus, but letrozole does not have those issues. And if my memory is working (it's been over three years!) the reason it's better is because clomid stops the body from using/seeing a particular hormone, but letrozole stops the body from producing that same hormone. One inhibits, the other blocks.

BW