As a first gun, I think a USP in variant 1 would be ideal. It would teach you how to operate both a DA and a SA handgun, as it really fulfills both roles with the manual safety, plus gives you the option to choose which method of carry is best for you should you choose to buy any other handguns in the future. A DA/SA Sig will not have that capability. As far as quality, they are both top tier handguns and my two favorite manufacturers. You won't go wrong with either gun, they are both top notch.
Jason
Jason