I just used a 2:1 mix of baking soda:borax to scrub down my shower.
No terrible fumes that require me to set up a fan to blow air through the bathroom!
Just about the same amount of elbow grease needed to get rid of hard-water stains.
Much less expensive than commercial cleaning products.
I'll keep using it. But I have to be CERTAIN to CLEARLY mark my little recycled sour cream container as "Tub Scrub" because borax is pretty toxic when ingested, according to wikipedia. I'm going to lock it securely when we need to baby proof*; even though it's so white and clean-looking, it's not a food (duh, right?) and shouldn't be used around food. That's good to remember.
*No, this is not an announcement of bun in my oven. I'm not expecting.