One issue I'm aware of w/ the 10mm STHP, at least with the lots I shot in the last few years and the chrono results reported by 10mm users on other boards, is that they're not near the factory claimed velocity of "1290fps."
To my knowledge, only Ron Reed of Reed's Ammo & Research loads the 10mm STHPs to that level - and he specifies 1300fps (from a 4.6" G20, IIRC).
Winchester uses a factory test tube of 5.5". Some of these posts report a wide disparity in chrono data for the STHP from the user's G20s and 5" 1911s or S&W 1006s: as low as 1150-1180fps, and some a bit hotter, in the 1200-1225fps range.
The reported variation in muzzle velocity aside, a STHP at 1180-1200fps is basically a mid-range load, in the same range as Hornady's 180gn 10mm XTP @ 1180fps - which is fine if that's all you want. But Win markets the STHP as if it's a
high-performance load, as developed in a barrel length no real-world 10mm autos use. Some also question how well a STHP at mid-range velocity will penetrate intermediate barriers, like wood of varying densities, metals used in cars and structures, and auto glass.
On the positive side, I've found the 10mm STHP to be nothing but accurate, and it reportedly expands well in ballistic gel tests. It's also apparently effective on feral dogs (per posts on
www.10mmtalk.com ).
Besides the DT and BB ammo, check out the 10mm ammo from CorBon and Georgia Arms. A lot of 10mm users seem to like GA's 155gn Gold Dot (@ 1375fps).
CB's 10mm ammo for self-defense uses 135gn, 150gn and 165gn JHPs (Sierras, I believe). CB also markets two dedicated 10mm "hunting" loads using a 180gn BCSP and a 200gn Penetrator bullet.