Dear All,
Hurdity, as always, has been exhaustive in her precious information, but I can give you my take. I was on Elleste Solo and Utrogestan for the first few years of HRT (having had early menopause), then was moved to Evorel Sequi, and this past month to Mirena and Oestrogel. Perhaps too soon to give you full insight into the latter, but so far so good; some women have found it not easy to tolerate it but then perhaps it's a general problem with tolerating progesterone in different versions. I have not had a problem with it.
As for insertion, I was on local anestesia as the surgeon had to remove a polyp at the same time, so I cannot say how difficult or easy. I was suggested to have the coil inserted years ago, when I switched to the Evorel Sequi patches, but I didn't go down that route because I hated the idea of having something inside me. However, I did switch eventually because I had too much monthly bleeding (and I have a condition that makes me anemic).