I have a G17c 3rd gen and G19 4th gen and love them both. The 4th gen fits my hand a little better and I like the texture over the 3G. I would guess the 4g G17 also has the dual recoil spring. I have several thousand reloads through the G17 and more than a thousand through the G19 with zero issues.
I think I paid $550 for the G17c and traded an HK USP compact in stainless for The G19 NIB.