I would ask all the people in the onsite broken SPI thread if they considered this engine to be reliable.
Any engine that runs fine for a time and then suddenly drops a valveseat the next time you start it is not reliable. Maybe one doing it yes, but MANY do it, enough to make anyone owning one worry when theirs will, that is absolutely not the definition of reliable.
How much better is the zetec? How about on average close to an additional seventy five to hundred thousand miles more life in many cases. I can't imagine anyone thinking that is a small advantage.