all the guns on your list are top of the line, with the rugers starting at the bottom, dont get me wrong rugers are damn fine firearms but in your list they will be the lowest price. out of these its realy personal pref. i my self dont care for the striker fired guns (glock,sr9) as much. however its the most used in us law enforcement (glock). the sr9 is fairly new and i have not heard much about it but comming from ruger i would think it to be ok. you cant go wrong with any of those, see which one fits you best. ps. if its 9mil. your into, check out the berettas (compact) they can be had at a good price and are dead solid reliable.