the EF-HI is pretty good as well and is a prety decent alternative to P21S wheel cleaner which was actually my first choice. at $20/gallon (and you should dilute it with at least 25% water), you can't beat it.
I picked up on this stuff over at autopia-carport.com (a BBS for detailing geeks).
griots may be a ine cleaner but it's not the holy grail of wheel cleaners. I think P21S would be the holy grail of the price weren't so high ($90/gallon). as you can see, EF-HI is a great alternative.
in liu of a wheel cleaner, you might opt for waxing your rims. I just tried that on my 330 and it works great so far. most of the dirt hoses right off. the remaining layer comes off easily with a spong and regular car soap. using a wheel cleaner subsequent to waxing will strip the wax right off. there have been some folks that have tried waxing their wheels with les than good results. since I have observed excellent results, I'd suggest they sprayed wheel cleaner on the wheels and washed the wax away.