I'm on bioidentical HRT - estrogen implants, micronized progesterone (Microgest), and spiro. It's working well.
Before that I was on patches and sometimes gel. Patches didn't work at all well, and my endo told me that not everyone absorbs estrogen well though the skin. Its the first time I'd heard of that, which goes to show the reason why we visit a decent doctor.
It appears that not many doctors do implants these days, but as far as I know they are by far the best way of getting estrogen. There's been a number of posts about them in the forums.