I would have bought a gen4 personally, and I have.... a G17, G34 and a G26 in Gen4
stop reading the internet, as reported less then 3% of glock pistol HAD and issue with either the extractor or Spring.... with new production those problems have been worked on.
end of story... I have 3k thru my gen4 G17 now, purchased 6 weeks ago with ZERO FTE, ZERO FTF.... I pickup the g34 and g26 this week in the mail and expect the same from them.