Quote by OBC:
"Let fit be your guide."
I would perhaps refine that to, "Let comfort be your guide.". Especially in a touring shoe. And it may be just semantics because comfort is generally derived from a good fit.
The fit has to be just right. Snug, but not tight. Adjustable for some swelling or flattening of the foot. A footbed that supports the sole of the foot. A toe box that is shaped to accommodate the toes. A heel cup that helps control movement of the shoe on the foot without irritating the Achilles tendon. Etc.
That said, most Sidi's are great shoes for 'some' folks. Worth the price? For those riders, heck yeah. But, if they don't fit, aren't comfortable or you just don't like the styling...there's about 20+ other brands that will provide you with comfort.
I've not noticed Sidi's marketing as being over the top. Their price schedule, on the other hand, trends toward the high end pretty low in their lineup so they do stack up as more expensive than most of their competition. You can buy last year's models and closeouts at a good discount if you know your size and have the time to shop around for a few weeks.