Me personally? I would NOT! The .40 produces more recoil (a sharp snappy recoil that affects shot to shot recovery), a louder blast from the shots, and the rounds have a much narrower tolerance for safe ignition than many other calibers. You can read about many of the .40 S&W Ka-booms (in several brands of firearms) that have occurred since the introduction. Yes, these can happen with any caliber and any brand of gun, but the incidence of them in .40 S&W seem noticeably higher to me. Function of a semi auto is dependent in part on the correct recoil spring weight for the round fired, and this relationship is more critical for the .40 S&W than for the 9MM.
A person ought to shoot and carry what that person can shoot and hold in their hand the best for optimum bullet strikes. That's different for different folks. What's best for you? Have you fired the .40 S&W much? You have a perfectly satisfactory handgun now. Will changing to the .40 improve on that? It's your choice for yourself so you must make it, but I suggest you ought to base your choice on your own criteria rather than mine or anyone else's! I also suggest finding a way to spend some time shooting a box or two of the .40's before spending the money to buy one. Rental fees and some ammo will likely cost less than what you will lose if you buy a new handgun and then find it to be unsuitable for yourself. Good luck with your decision.