The answer is: Yes. :) No seriously, we install both aluminum and steel gutter. Usually we recommend a .032 aluminum K gutter with a baked on finish for sloped/shingle roofing. Why not steel? Well the cost is prohibitive and the steel gutter won't necessarily last any longer than the aluminum. This is pretty typical for residential roofing. Although some cheapo contractors will try to sell you .027 aluminum gutter. This is flimsy "builder grade" cheap material, very prone to damage. Aluminum gutter is also available with premium paint finishes like Kynar and Hylar which really jack up the price.
The aluminum will not rust or rot out like the steel will eventually. Even though it's painted, eventually it will begin to rust. This rust will usually form at the exposed edges and cuts. From there the rust will spread like a cancer.
Having said that, on flat roofs we most often install custom bent G 90 galvanized self flashing box 24 gauge steel gutters. Why steel? Well some low slope roofing systems are heat applied. The heat necessary to create a proper bond will actually warp and bend the aluminum, therefore steel becomes necessary. However with other membranes which use adhesive instead of heat to apply, aluminum is preferred, but also more expensive.
So to summarize the material is important but so is the of gutter dependant on the type of roof you have.
Source: http://gutterexperts.com/