Stupid question, but what is the velocity gain and power gain over say a 40 or 45? And how is the recoil?
A couple hundred FPS at the upper end over a .40 (IIRC, don't have my loading manuals at the office!). For a given powder and bullet, starting (listed) charges of powder will often be higher than the max in .40. And the speed/KE advantage over the .45 is big.
Now, there's the question of what that extra speed is worth. It flattens trajectory, if you're doing lots of 100 yard shooting with an autoloader. It's currently out of fashion in the terminal ballistics world to believe that speed in handgun cartridges has any special benefit in and of itself, but if you believe in hydrostatic shock in the 1300-1500fps range, then there's that. And with an appropriate bullet, you can get more penetration - useful for hunting more than "social" applications.
The longer case also means that a 10mm is better than .40 when it comes to heavy bullets (e.g., 200 grains). It just has more case capacity to spare. That spare case capacity also may provide a margin of safety against/for bullet setback, long discussed as a particular bugaboo of .40 rounds.
And if you really like a pistol format that works better with longer rounds (such as, for example, the 1911), then you may get better/easier reliability with a 10mm than a .40.
Recoil is subjective, but I don't find it punishing. If you can shoot .357 magnums, or soft .41 mags, without complaint, then you'll find the 10mm easy to handle. Recoil will generally be snappier than a .45, but with the lighter bullets (155 or even 180), the overall push may feel less "big" than .45 hardball.
Of course, if you handload, you can run up and down the power spectrum, from very soft plinker loads all the way up to KE's that overlap with .41 magnum levels.