Originally Posted by Burton

For a touring rig I'd take titanium or steel over carbon fiber or aluminum any day. Not because the those materials are inferior, but simply because those other frames use derailleur hangers and derailleur hangers haven't been standardized. Working in a shop I'm aware that there are currently over 20 pages of jobber hangers on the market intended to replace hangers that different manufacturers have stopped supporting over the years. I guess anything is available if you're willing to wait long enough and pay enough money - but most touring cyclists have at least a timeline to respect.