I Agree Dave, I've was introduced to X-10 Systems somewhere around 2008.. True, the little ninjas at that time were not super, however, they provided decent / sufficient viewing for general surveillance etc. Are these the same components used on many of the newer models, I'm not sure, but still provide a decent surveillance for the pricing being that I recently purchased 2 Air Pro 42s.
It basically comes down to who are using these cameras and what surveillance they are expecting to achieve. I havn't bought the PTZ Pro HD, but i would probably say the quality would be a great deal better viewing than the older models, however, as with all, you will pay more. If it is as great as advertised, I would say it is a very good deal being that many other High rez cams are well over $500.
Anyhow, just my personal take on this thread.