I own two excellent Austrian 9mm and Austrian .357sig pistols that I have complete confidence in.
I'd choose the .357sig if I could only own one, for its overall greater range of application. The lab and backyard tests I've seen with .357sig caliber demonstrates to me that both bonded and non-bonded .357sig ammo has excellent hard barrier penetration capability.
It could be that most civilian self-defense scenarios don't involve hard barrier factors but defenders don't get the option of choosing the time and circumstances of the encounter. For this reason alone I find myself moving towards bonded ammo when I rely on my 9mm pistol. I don't really have a pronounced preference when I'm relying on my .357sig.