We're not sure why Marzocchi's new XC family is called 'Retro' as its blend of proven design in new packages seems far from old and ideal for today's trail bikes.
The XC500 is the shortest travel version at 100mm, but it still suckles away smoothly over ripples or larger hits. Its noisy open bath damping constantly milks the ground for maximum traction, while the fork top TST 5 (Terrain Selection Technology) dial gives you five different compression setups for various trails. We generally only used three (full open, mostly open and locked) and relied on the twin low pressure air chambers for more detailed set up though.
32mm stanchions make this short-ish fork feel impressively stout on the trail, yet that's reflected in the high-ish weight. XC family reliability seems excellent as usual for Marzocchi, and while the right hand air screw is a little awkward to get to, you won't need it too often. Hydraulic hose clip keeps routing neat, post brake mounts are easy to set up and you can even plug in V-brake mounts if you want.
XC600 and 700 up travel to 130mm (in next month's test) but aggressive pricing makes the XC500 a great value tough trail choice.