The latest XTR is the lightest around and there are loads of variants to choose from.
Shimano has followed SRAM's move by using a broader linkage. More positive, faster shifts and careful cage sculpting give the most effortless feel of any front mech. The lightweight alloy cages are nickel-plated for longevity, too.
Dual cam head means it'll run with top or bottom cable systems, and the angled adjuster screws can be got at through most suspension setups. Top swing rollover mechs are lighter and more compact for £54.99, while £59.99 E-type mechs are available for mountless bikes, too, so pretty much anyone can benefit from XTR.