The eVent fabric used in Pace's 3x3 jacket appeared several years ago to great fanfare. There were bold claims of breathability way beyond any other material, thanks to doing away with a polyurethane layer and just using microporous PTFE but chemically treating it to resist the contamination that the PU layer would normally deal with.
Lab tests have shown that eVent can be twice as breathable as other fabrics, with the considerable advantage that it works equally well regardless of the relative humidity levels inside and outside the jacket. It starts transporting moisture earlier.
Pace’s 3x3 jacket is a superb performer. It relies on eVent’s breathability to keep you cool, so there are no pit zips. We didn’t miss them, but heavier perspirers on warmer days may do. You don’t get many other features – a single pocket at the back, a drawcord collar adjustment, Velcro cuffs and some reflective piping – but the 3x3 is great for areas like the UK, where it’s often wet but warm.