I had one for a few years and sold it this summer when I decided to sell my bonsai with larger leaves (and consequently needed to be larger trees) since my space is limited.
I really like the flowers and mottled bark, but it wasn't my favorite bonsai material. The growth was slower than other deciduous material I've work on. Not that I was refining the tree, but I didn't get the impression the leaves would reduce well, and they are pretty big to begin with. The internodes were also fairly long, and the buds didn't always reliably live and grow after pruning. Since the internodes were long, I'd want to prune back to 1 node (with 2 buds). If one bud dies, you just don't get ramification, but if both buds die, you end up with dieback or losing the branch. I'm sure if I would have kept at it, I'd learn the habit of the species better. I almost planted it in-ground, but my municipality actually planted a dogwood on my property this fall, so I let it go cheaply to someone who was buying some other trees from me.
