Over the last 25+ years, the G20 is definitely the most versatile autoloader that is chambered for the world's most versatile "service cartridge" extant.
The 10mm's huge power curve allows you to choose from among numerous factory loads using JHPs & FMJs of various weights and styles. Factory loads range from "mild-to-wild" - from range-plinking ammo to the near-nuclear, from target or competition-level velocities (which for the 10mm are generally .40-level or a bit hotter), to mid-range loads for CCW or duty use, to the "heavy & hot" screamers for hunting or protecting yourself when you're out in the backwoods or bear country. With the G20, you've got the 2- and 4-legged predators covered with an easy-to-pack, 15+1 magnum autoloader of reasonable size and weight. Yep, you can leave that 6 shot boat-anchor of a wheelgun at home, which is the same reason so many of the flyguys and hunting guides in Alaska have replaced their big-bore revolvers with a G20, which they load up "heavy & hot".
Available bullet-weights for the 10mm, given such a wide variety of possible tasks, range from 135gns all the way up to 235gns. Several of the heavier slugs (those exceeding 200gns) are offered in cast bullets.
Once you have a G20, you can also buy aftermarket barrels for it from any number of vendors in .40S&W, .357Sig & 9x25 Dillion. All you need are the spare tubes. These other cartridges run w/o a hitch with the G20's stock 10mm magazines and recoil assembly because their cases are all derived from the 10mm. Think about it - you can shoot
4 calibers from one gun with its stock mags. If you swap in a G21 upper barrel & slide assembly, you've got
5 calibers, all off the same platform. You can do all of these things too with the G20's little brother, the G29.
As far as extra barrels myself, I've got an LWD 10mm stock-length (4.6") tube, w/ fully supported chamber, for my super-hot handloads as well as for shooting cast bullets, and a very old Federal Arms (also stock-length) .40S&W tube for that ammo. Reliability is 100%.
When shooting the near-nuclear 10mm stuff out of the LWD barrel, I use a 24lb ISMI XP recoil (non-captured) spring on a SS rod.
This set-up is very accurate and, again, runs 100%.
Get the G20, ignore the naysayers, and don't look back.
Hope this helps ...