Up here in northern Wisconsin these roofs are very common. I've been
thinking about going to one myself when the current roof needs
replaced. Here are the pros and cons that I've heard from others:

Pro:
Very easy to install. You should be able to really save on labor
because you can just roll the metal right over the shingles.
Good environmentally because you aren't producing and then pitching
shingles every 20 years or so. Also, you can recycle the metal if you
do have to remove it.
Looks nice, lasts a long time.
Snow slides right off of it, so no shoveling the roof (also a con
though, because you lose the insulative value of the snow).
Sound of the rain on the roof (this could be a con if you don't like
that.

Con:
If you have skylights or other protrusions (chimneys even), it is very
important to get the roof done right the first time around those
objest.
Much harder to do a patch job than it is with shingles.
Likewise, if you want to add skylights or something later, much harder
to do properly.
Cost--though I haven't heard of it being as expensive as what you were
quoted. Not familiar with that brand.


If I end up going with a metal roof, I will probably first do much
research on what type of metal to use. For example, I might build a
cistern at some point, and I've read that you don't want recycled
steel as the roof because of some contaminats that would get in the
water. I've also heard that some people used copper (those people
must have a lot more money than me) and then had their roof stolen by
salvagers when on vacation. (Probably just urban legend, but the
point is think about what kind of metal you are getting for you
money).

Good luck!

Hope some of this is helpful.