I have Bartzilla and Keiko (yellow and pink)
If I only got one more would you recommend-
Kopper Kettle, Pastel Splendor or Hillary
I have quite a few types, but my favorite one is the Cora louise.
Why is your favorite Cora Louise? The color seems similar to Pastel Splendor.
I think the fade from purple to white looks pretty cool along with the yellow pollen in the middle. It looks similar to the rockii tree peonies which I don't think I have yet, but I have so many tree peony seedlings that already have distinctive looking leaves so it might also be in my collection already.
Misaka looks pretty good, and I might get it if I find a good deal on it, but I have enough of an itoh peony collection so that it's not really necessary.
One thing about itoh peonies is that they propagate really easily as I managed to get literally a bud to turn into a little plant with a bit of rooting powder of course, but it worked. If you are buying one, you really don't need a big plant or many of them as they grow pretty fast as well.
I have Garden Treasure, Kopper Kettle and Cora Louise. My favourite bloom is Cora Louise, but I am partial to the rockii look. (It is too young to say much about the plant habit.) Kopper Kettle has a good plant habit and is floriferous, but I find the colour just a bit muddy. Yes, it does have all those shades, but the overall effect is a bit of a orangey-brown, at least for my taste. Here is a photo of Kopper Kettle.
I have 3 bartz, 1 high noon , 1 pink (first impression I think its called) , 1 garden treasure (I gifted to my dad and quite frankly for a yellow ...wimpy wimpy wimpy, The Kop Kettle I do have and will agree its a toss up between Bart and kop. The barts bloom late like most itos and barelr last 2 Days if lucky. The itohs are great BC of their cross resilience making them almost perfect health wise. None of them smell so don't believe the hype and if the do its probably whatever is planted next to it. If you want to make a beautiful statement that will turn lots of heads, get your hands on a fern leaf peony as red as you can find. itohs need that decade break or 2 just like and trend in life. Good luck!