I have many of both. They're quite comparable. Even so... I have a preference for bloom-a-thon. They do seem to bloom more and the foliage tends to look healthier. I'm in much different conditions than you though... and both really are wonderful.

Oh! I just thought of something tho that might make a difference to you. Encores are evergreen so they keep their leaves all the time. Some have nice autumn color too. The bloomathon are semi evergreen. So they lose their internal leaves and keep just some leaves on the tips of branches. In my yard, the lavender one does this the most. The others seem to keep their leaves.

When it first happened I was worried something was wrong until I realized they weren't totally evergreen. If you want a leafy bush all through the winter, you may want to stick with encore.

I have some of both. Encores come in many more colors. But I like the foliage of Bloomathons better - especially Bloomathon 'Red'. Both are semi-evergreen for me. I'm in Northern VA.

Thanks for your feedback everyone. As of now I how Encore Autumn Twist. I really love the flowers and variations in them. However I have never really cared for the plant itself. They always look too open and not full as I like. I have planted Vintage Jade Distylium in front of them last week trying to hide their lower part. I really like the Bloom-A-Ton that I see at the nursery. The only reason I have not jump and pick them up is their cost. They are almost double the encore ones. Would love to hear more thoughts on these two.