I'm late to this thread but was faced with the same decision as the OP. Like many, I cut my teeth on the idea that the .45 ACP was the ultimate in all things autoloader. Well, I changed my mind and went with the 29 in 10mm. I've found a good selection of 10mm at reasonable prices for practice. I just got in another 150 rds FMJ which cost $57 shipped.
If handloaded, this cartridge has the power of the late lamented .41 magnum. Since my mission for this arm was pig hunting and using it as a backup for my usual carry, the great penetration carried the day for the first task. When loaded for defense, the Hydrashocks should address excessive penetration.
There's a huge kicker that yields enormous benefits which, when considered, made my decision stone simple: I can shoot 40 S&W for light and inexpensive practice. I've run many such shorties through the 29 with no issues and not a single misfire. Accuracy is as good as I can hold.
Looking back, I feel my going for the 29 over the 30 was me making one of the better decisions that I've made - at least lately.