Underwood is within SAAMI specs pressure wise. They get this velocity by blending powders and optimizing for real world barrel lengths. These loads shouldn't cause any more wear than the lower powered stuff if you upgrade the stock spring setup. I like 22# in the g20 and 24# in the g29. I personally like the 165gr gold dot load they offer: http://youtu.be/cLrJD_0yvBo
I have a bunch of the Underwood ammo for my 10mm. It's literally a blast to shoot. Pretty accurate too.
When you get tired of the hot stuff, try to catch Freedom Munitions when they have it in stock. It's 180gr rated at 1200 fps, which is right in between the real mild stuff (American Eagle, Armscor) and all the full power loads from Underwood, Corbon, and Buffalo Bore. UMC is pretty decent at 1150 fps, but about $10 more a box than FM.
I ordered some of the 10mm from Freedom Munitions last week when they were having the free shipping. The FMJ was $22.25 per box of 50.