I haven't had any issues at all with my fairly small Insteon install *crosses fingers*. I will definitely invest in an ISY before expanding on it as the linking method is painful to say the least. For me, it was a cheaper alternative and like I said, works as advertised. When I wasn't pleased with their economy switch (ICON) I sent it back and no problems.
I agree that Smarthome has had many issues in the past and has a lot of work to do to improve their image but I wouldn't let a few people sway judgment completely on the technology. Personally, I don't have the time or desire to continually applaud Insteon's success in my home but when people have bad experiences, they tend to have nothing but time and effort to do the opposite.
I would never claim that Insteon is the best, as there clearly is a reason why its not the most expensive (and generally easier to install than other techs). Smarthome seems to be continually releasing new Insteon products, often in response to customer demand. With a decent boost in QA and PR for that matter, they could really be formidable.
For me, Insteon is simple and that's what I wanted. If I had the know-how for more advanced techs I would venture there, but HA is just one of my many mini-hobbies at my house, so I can only spend so much time on it!