Back in my misspent younger days we raced Hondas and used ATF in the forks and the rebuild-able CR250 shocks we ran on our bikes.

The ATF worked pretty well, good damping that didn't fade even when they got too hot to touch, and didn't leak out past seals.

ATF was easy to find and cheaper than fork oil, an important consideration when changing fork and shock oil 6-7 times a season

Has anyone ever used it in BMW forks, or is it too cost efficient to work with our bikes?  Does anyone know of any seal incompatibility?

Been using it for years and have recently converted to Synthetic
http://www.ebay.com.au/itm/GULF-WESTERN-AUTO-TRANSMISSION-OIL-SYN-TS-SAE-10W-8L-TOYOTA-SOARER-JZZ30-1JZ-GTE-/302085002758

Used ATF a lot during my dirt bike days...tried it in the K100LT, 1990 model, but found it too stiff for my tender and aging bones. I think I finished up using Castrol 10W fork oil, and that seemed to work OK. I was v.careful to put the correct amount in. At no stage did I suffer from leaking fork seals.

I've been using ATF for well over thirty years in every bike I've got/had (and in all the rebuilds I've done for other people). It's a good 10w oil and half the price of fork oil. At a push even 2T will do if nothing else is available.

Sounds like a solid vote of confidence.  With three bikes in the garage that I would like to change annually, ATF is an attractive option vs. fork oil.