look at malarkey shingles. they have a new asphalt they are using. when you look at asphalt thats been used in all shingle manufactures for years its really interesting how its made. with conventional asphalt for shingles they force air through it to get the melting temp where they want it. meaning, the asphalt is very viscous and softening point is low. so they force the air into it which raises its softening point. it basically ages the asphalt.
malarkey's new asphalt is not oxygenated, they actually use a lot of recycled rubber, carbon black they get out tires, etc so it doesnt have the air forced through it like conventional asphalt.
what this does is grabs the granule better where as the traditional asphalt is already hard or harder. it doesnt grab the granules as well. then years down the road when you see all the granule in your gutter you wont see that with the new asphalt like malarkey has.
also, their new granules are smog eating granules. 3m makes this for them. its kind of proprietery deal for them for a while.
up untill a few years ago all shingles were 30, 40, 50 year.. i think GAF changed the market and made them all 'lifetime' doing away in the market as 30,40, 50 year. also, shingles were reference by weight, well GAF doesnt even list a weight. There timberlines weight about 200lbs a square if that. certainteeds is about 245, untill malarkey went to the new NEx gen asphalt thier highlander weighed 247, now its 23x lbs. Pabco makes a real nice shingle and is heavy. pabco probably has the best warranty in the market too but malarkey will match anyones warranty if you are really concerned about it. warranties are written for the manufacture, not the home owner.
you can install a curved roofing panel that is not exposed fastened. look at any mini-batten panel. I know for installers, they can get an on-sight tool to curve the panels if need be and manufactures such as AEP (which is ASC) will curve them for you in the shop and send out if you get them the radius. you can also use a 2" mechanically seamed panel too. concerning the oil canning, all panels will oil can ecspecially if your using 26ga or less. never use 29ga unles you just dont care. to get away from oil canning go thicker and narrower on the panel, eg 22ga and 12". all panel manufactures now days give you a paper and some make you sign stating your aware of the oil canning and they recommend striations or minor ribs.
I push the mouse around a computer 8-10 hrs a day as a commercial roofing estimator, i dont deal much with residential although i take care of all the residential metal roof estimates. i can get technical info for you if you need any help. im not an expert by any means but im sure there is a few running around here
as with anything, need to pay attention to the details or youll get screwed. doesnt matter if its comp, metal, tile, or whatever.