Like the .41 Magnum, the 10mm is, I believe, under-appreciated. It is an excellent cartridge, but one that few makers build guns for and not likely to see any upsurge in popularity any time soon, if ever. To me, the real value of the 10mm is only found with high-end loads, where it can beat the pants off of either the .45acp or the .40. W/W Silvertips will easily clock 1250+ from 4-5in. barrels with no more recoil than 230gr. ball in the .45. If you want to reload, and take time to find brass, the 10mm can do anything either of the other calibers can do, and do it at much lower pressures than the .40 S&W. Unfortunately, the 10mm requires a full size frame a la the .45 and is virtually impossible to build in a compact model. The G29 is not what I consider "compact". All in all, the 10mm is mostly an "enthusiasts'" caliber.
The .40 ain't a fad by any realistic stretch of the imagination and it won't go away for a long, long time, probably never. It is a pratical and extremely popular defensive caliber with a wide variety of handgun models available to fire it. If you reload for it, you must be very careful as pressures can go "off the chart" quickly...see Sig 230's posts on this. If you are not really "into" handguns yet, get something other than the 10mm for a start. The 610 revolver can, of course, do it all, but in a pretty big, bulky package if concealment is a consideration.