I assume you are talking about the p10 compact which is a striker fired gun and the shadow which is a hammer DA/SA gun I would take the shadow because I prefer hammer guns but I suggest that you try to handle both at a local ffl and get the one that feels the "best"

Glenn, they are similar in features and function. This will be a personal call. That being said, my choice would be the Shadow Compact as I have handled/shot my brother's and it was fine fitting and fine shooting. You really can't lose with either.