Just read whole thread, and will add:
a) I have a (mirena) coil, fine to use mooncup although yes better to break seal first.
b) I sterilise with a milton tablet at the end of each period in old plastic cup I keep in bathroom and use for mooncup only. Didn't fancy boiling it in a saucepan I use for food.
c) yes possible might help with cramps....
d) another benefit for me is in gym changing room no strings hanging or no pads in knickers..... great for swimming.
I am only v lazy and honestly think lower maintenance than anything else - eg don't have to remember to buy supplies (ie can't run out) plus need to be changed much less often during period. Have whole month to get round to sterilising.
I do keep panty liners in desk drawer as periods starts out light for first few hours, don't want to carry mooncup around or leave at work, but for me periods not v regular. If totally regular added benefit of being able to put in place before it even starts. And if going on holiday takes up less space than alternatives.....