Hey Peter, this is at least as breathable as other "normal" body armor I've tried. The VPD panels are perforated for better airflow, and the zip-up jacket material itself is quite stretchy and breathable. It's some kind of micro-mesh that's more porous than it appears in the picture here.
It really does fit under a T-shirt. Flexible and moves with you very well. I was skeptical about the elbow/arm pads lining up with my super-long arms, but the material is some kind of magical uber-stretchy substance that seems to conform to whoever is wearing it. Haven't taken anything more than minor to moderate spills as of yet, but very, very happy with it so far.
Insane grip, perfect stiffness, and super comfortable. Can't ask for more in a riding shoe. I much prefer flats to clipless and wear these for everything from XC rides on my hardtail to chairlift laps on my big bike.
The ride is softer than you'd think for a hardtail thanks to the steel frame and 29" wheels. Still getting used to sitting up a little higher than a "normal" bike but it still feels quite nimble through winding sections. Love the frame and fork, may upgrade components here and there but it's a solid build and a great value.
Best rack I've ever owned. Takes under 10 minutes to assemble, 1 minute to attach to your hitch, and about 10 seconds to load up each bike. Securely holds everything from my BMX to my 29er to my 50lb downhill rig, without them bashing into each other (even on bumpy roads).