I chose the Shield in 9mm because I already had two other 9mm pistols and want the convenience of same ammo for all. But before I purchased the Shield I made a trip to a local range and rented Shield and Walther PPS in both .40 and 9mm. After shooting them all side by side my decision was the Shield9.

Deciding factors were the Shield felt better and, for me, pointed better and therefore was more accurate than the PPS. And at least for me, the .40 in both pistols was snappier and more difficult to recover the target after a shot. The Shield40 was a bit less recoil than the PPS40. I realize more practice with the .40 might change that, but the strong weight toward having same ammo for all swayed my decision.

Then all I had to do was find one available for a reasonable price, which turned out to be a 4 month search but wort the wait.