There are a couple of other makes, but most of the other ones around are clones of the Moteck, Jaeger or Stab (in fact the Moteck was originally a Jaeger clone I believe).
If a dish were to be mounted in an exposed position, then I would be inclined to limit the size to 90cm, I have not yet heard of any incidences of motor arms dropping off, but there is obviously a limit as to how much weight it is sensible to hang off of one.
