To each his own, I guess. I'm currently in a phase of not having enough echinacea, although that's really not the case. Since the butterflies and hummers can't seem to get enough of them either, they'll always be in my beds...

Never had a problem with them, they self-seed quite regularly for me, but I have the old fashioned purple ones, not a fancy hybrid, so that there probably contributes to its hardiness and willingness to self-seed.

I've had Mangus and White Swan for around twelve years, never had a problem with these two. I do water them once in a while, not often, usually only when prolonged heat with zilch rain. They have a tendency to droop their little heads and whine ( actually defend themselves) when the moisture levels are really low and the sun is beaming. Little Praying Mantis are staked out on mine this year, don't know what they are hunting, but have not had any damage from insects.

If you go with Rudbeckia, you'll find them to have a few problems also occasionaly , but like you said these are all mainstays of the midwest garden.

I know Ecinaceas are common as dirt around here, but they really are workhorses. I've got some planted in part shade & they bloom when nothing else will. I refuse to baby mine, no fertiziler, no mulch, no extra water. I have to make sure I deadhead them before they go to seed, or I'll be pulling Ecinacea seedlings all the next summer. I do leave a few for the goldfinches. I started off with some White Flower Farm plants & a couple of local 1s from the native plant group here. Now, I have some hybrid of the 2, & they're virtually indestructable.

No matter what cast iron plant you suggest, there are people who will have some sort of a problem with it....
The cone flowers in my garden are worry free.
If you don't believe me, look at the people having trouble with astilbe and hosta.
If you substitute phlox for echinacea, they will get mildew, the helianthus will grow too tall and fall over, something will eat the petals on the ratabida and the rudbekia will reseed all over.
It's always something with a garden.
Linda C

Even here in the sunny South, echinacea is a dominant flower in my garden beds. It has been thriving in my clay soils, in the middle of a drought. Naturally, it gets occasional watering if it doesn't rain. I'd consider it to be exceedingly productive and easy to grow.

We enjoy all of those goldfinches, too! They are so pretty, flitting all over the place.

Weird, isn't it? I can't water regularly and it has been SO dry each summer since I moved here (8 years now). So plants truly have to be drought tolerant and echinacea have been a star for me. They don't self-seed excessively but enough that I have plants for new spots or friends. I have Magnus and White Swan as mainstays. I currently LOVE E. paradoxa and E. pallida although they are taking a while to get going. Sprung for a $25 "Sunset" 2 years ago - learned my lesson. It is okay, a bit small, but not worth that money. Quite content with my old-fashioned ones. Wish I could make them work for you, bean counter. They really are wonderful.