The most unique thing about the M5 (Mugen 5) is that for the first time in Mad Rock history, their concave sole features a flat sole design. The flat sole gives it a more relaxed fit without the toes being "down-turned" like more aggressive concave designs. The concave aspect allows it to grab and hook onto steeper terrain like the down-turned designs while the flatness keeps the toes from being unnaturally bent. A custom molded mid-sole gives the right blend of rigidity and sensitivity. This design gives a fairly high amount of overall performance balanced with a relaxed and comfortable feel.
The other new design feature is called the Arch Flex which splits the sole into two sections, front and back, allowing greater overall flexibility. The Arch Flex is also connected to the Velcro straps making it easy to adjust tightness. Heel hooking has improved with the new Torque Heel design. Our tests showed a slight improvement over the old ribbed design even though it fit a bit loose and airy (that could have been due to our tester's foot shape). On the business end of the shoe, the toe tip is rounded and very good for most edging and smearing (frictioning) but is not pointy enough for some tiny pocket footholds. The sole has a soft center for sensitivity and combined with a firm border for edging makes a very nice mix. The dual thicknesses complement each other well.
Looking and feeling slightly similar to the popular and more aggressive La Sportiva Solution, the more relaxed M5 surprised us with how it kept pace. The main differences between the two shoes are the down-turned nature of the Solution toe and the strap system. The Solution has a more aggressive toe that is better for steeper, more difficult moves where the M5 is flatter and good at multiple styles of climbing. The Solution also has only one thin strap and the M5 has two standard size Velcro straps making it much more adjustable and secure. The M5 also costs about 30% less. All in all, the M5 is great for someone who wants a shoe that can perform moderately well at most styles of climbing and is also comfortable and affordable.