It all comes down to getting used to it.
The majority of pistols today have the side release button so that is predominantly what American are used to. Id does not take long to get used to a bottom mag release but it is undoubtedly slower. The HK P7 style is nice because you actually make a motion of pushing into the grip with your thumb as your curled index finger is pulling down in the (extended and serrated) mag floorplate. This is faster than the heel release of say a Ruger MKII or Walther P38 where you have to actuate a lever on the bottom of the magazine itself and push it away from the grip of the gun to the rear and then try and pull out the magazine.The P7 release is more ergonomic and faster and is really in a league of its own in the world of the European heel mag releases.
The two pistols I commonly use are the P7 and Browning Hi Power. If you have experience with the Hi Power and the dreaded magazine safety then you know that the mag safety rides along the magazine as it is in the mag well and hinders it from dropping free when it is empty. Since I used the P7 first and grew accostomed to using both hands to release the magazine I quickly warmed right up to the Hi Power and its inability to drop its magazine in the fashionable way. ( I have my magazine interlock in place on my Hi Power). This is just an example of being able to readily transfer from one pistol to another with different magazine detachment methods. Given your choice of pistols.
If you find yourself accustomed to the heel release and try to transition to the button release, I think you will find yourself ejecting the magazine with both hands even if it is not necessary. I dont see this as a bad thing as a second lost to ensure a proper magazine change is, I believe, a fair trade-off.