The Gen5 Glock 17 features a modified trigger action that will not accept older aftermarket parts. The pistol features a true ambidextrous slide lock, a grip frame that fits most hands well, and a new-style flared magazine well
The Glock 20 was a soft shooter. The girth was larger, but manageable, and the trigger was a Glock trigger that could be improved with an aftermarket kit. Plus there are numerous other parts to customize the pistol.