Personally, I like/use Prestone. In my streetrods I use Prestone Dexcool as I have some aluminum parts in them. Personally, for my 900, I buy the 5x stuff they produce.
It's apparently formulated to extend the life of the antifreeze and should give excellent corrosion protection.
I know you can buy a lot of brands cheaper but I've had good luck with Prestone and I'm not about to change for probably $10 or so. Replacement parts are a lot more expensive than antifreeze.
Check on the instructions, you may not even need to use distilled water with them but I do as again it's pretty cheap insurance.