The Solution Comp is an updated, softer, more sensitive version of the classic Solution. As the name suggests, they are designed for maximum performance on climbing competitions.
The most obvious difference is the heel, unlike the Solution, the Solution Comp has a soft, thinner, lower volume heel which should fit a more extensive range of feet than the Solution. It also provides great sensitivity when you're heel hooking making it excellent at heel hooking tiny features. The toe also has even more rubber on top for catching toe hooks more easily.
The 3.5mm Vibram®XS Grip2 is Vibram's softest, stickiest rubber perfect for smearing on small micro holds on steep ground. It also has s a 1.1mm Laspo flex midsole that supports your foot enough to be great at standing on small edges but keeping enough flex for smearing. They keep the P3 system from the Solution to keeps the shape of the shoe throughout its life, so they maintain their performance.
Upper: Combination of suede leather with microfiber, tubular construction
Lining: Pacific toe, Lycra® tongue
Midsole: Hytrel anatomical support of the metatarsal arch combined with the P3 system
3,5 mmVibram®XS Grip2