Thanks for the replies guys. I had just finished trimming and thinning a dwarf Hemlock. I thought about how the tree as I worked, realizing how long I've had it and how much other trees have developed in the same time.
The tree has definitely grown vigorously, but all in the wrong places. Very little terminal extension on the apex and branches and tons of buds on the trunk. Took two days clearing them off so I could see the actual trunk only to realize at that point that I was polishing a turd.
My other dwf Hemlock resembles a Birds nest Spruce, with hardly a trunk and all the branches spreading laterally with barely an upward twig.
I have had better success with deciduous dwfs, but not all. I have found that with most you must not cut the top back or they will not grow upward again, only outward. I have a Hups dwf Japanese Maple I removed a side branch and only a few little buds replaced it and they have not grown out but a half inch. They just sit there, not extending, very unmaple- like.
I tried a Morris Midget boxwood. I love boxwood, but that little tree fought me all the way, even in ground it just sat there while my Kingsvilles flushed and flowered. I trimmed the roots at planting and it just never got over it, finally turned brown.
So what do I think? Well, I guess you have to look at each. There are degrees of dwarfyness. The more extreme the less likely to be usable for bonsai. The Hups Maple is an extremely dwarfy dwarf, Makawa yatsabusha not so much, but still a small tree, showing ten times the growth in the same time. I'm shying away. Standard trees with applied techniques produces satisfying results much quicker.
That's the whole point. I thought dwfs would be a great shortcut, hey, they're already small, right.
