Dustin, This will simply boil down to your physical size and intended use Sir. They are equivalent in features and function separated only by physical size. Whichever size works best for your needs will be "The One". Cheers and stay safe!

Pretty much James hit it on the head. The real only difference is the 17 is slightly bigger than the 19. If you're possibly planning on concealed carry then the 19 is your best option. If you want home defense, or just a fun pistol at the range I'd probably go with the 17 since the size and weight will make it more pleasant to shoot. They're both great pistols that will serve you well, just depends on it use. Hope this helps and good luck in your choice.