The Gen5 preserves the reversible magazine catch of the Gen4, but goes one step further by incorporating a truly ambidextrous one-piece slide lock. That's a nice upgrade for you lefties out there.
The magazine and mag well have also been overhauled. The magazine now features an orange follower so you can visually identify empties, as well as an extended lip for grip. The mag well has been flared for faster reloads. The finger grooves are now gone, and the front strap features a cut-out for extracting the magazine. Bottom line: it's the same Glock you know and love. It's just a little more shooter-friendly now.