Muzzle rise (flip) and felt recoil (shock) are not the same thing, personally I find the muzzle rise, gun control generally better in a 5" 9mm than a 4.5 " pistol but felt shock may be less in the polymer frame pistol. Why? Shock, felt recoil is like a sound wave it travels faster in a more dense material, but generally the heavier the pistol, less recoil is felt, but polymer does have a dampening effect. That could explain why the small Glock G19 shoots and feels like a much larger and heavier pistol... hmmm this makes it clear as mud as to which has less felt recoil Beretta or H&K P30l. She would have to try both, personally I like the Beretta, except it's backward slide mounted safety. I would also have her try a 1911 chambered in 9mm with an all steel frame and slide. For less than either of the current choices, the Taurus Pt1911 9mm is an incredible shooter, with all the same features and a better trigger than 1911's 3 times it's price. My smoothest shooting most accurate 1911, is an STI 1911 in 9mm. If I had to make a choice between the H&K and the Beretta, and could not try each before buying, then the Beretta has cheaper magazines, and you can actually find a holster to fit the 92 at most gunshops. H&K nice stuff, good pistol the P30 but magazines start at around $49,and a holster made to fit is harder to find.
