There are quite a few iris I would place near the top of my list, but whenever Iris cycloglossa blooms for me, I am struck by the elegance of its colors, form and its heavenly fragrance. It is so distinctive it's hard to accept that it's a juno. Seems to me to be in a category of its own. I have always had the best success with it tucked by a stone or a wall. I wish you could sniff it!
This too ranks very high on my list of Iris, and I'm similarly surprised some enterprising botanist hasn't separated this out and away from Juno... it has such a totally un-Juno appearance. Mine came and went over in a mere two days recently, as both days reached about 94 F (35 C) putting a quick hastened end to flowering on a number of things blooming at the time.