It really depends where your priorities lie. The VersaChuck with backplates is definitely a good idea (I have two of them), but changing the backplate can be a bit of a pain, as it requires three allen screws to be removed and then the backplat itself to be wiggled out of a quite tight fit with the chuck (which is actually good, as you don't want to add any runout).
On the other hand, the thread adapters work well, and a lot faster, but you do lose 2" of length between centres. Shouldn't matter that much on a Hegner lathe, if I recall correctly they have quite a long bed.