I like wraps/skins on my MBP. Cases retain more heat, even with those supposed venting holes and if/when any dust or other abrasive particles makes its way between case and laptop, it'll scratch it up eventually. Gotta periodically take the hard case off and dust it / air blast it and clean it inside and out. Lastly, the weight addition. Could add an extra pound or so to the weight of the laptop and its lightness/portability is one of the best things about it.