I always hear about the disadvantages of a timing belt and how it is a $300 job every few years or so, depending on miles driven. Other disadvantages include you being stranded with a non-running engine until the belt is replaced or the worst case of an essentially trashed engine from the valves crashing into the pistons or vice versa.
Are there any real advantages to these compared to timing gears or chains? Are they better for fuel economy due to a lighter mass or is there any other practical reason for them besides getting you into the shop for a replacement or worst case a new car if you neglect them?
Conor