I have one, and I get 5.4% interest per year. On June 1st, they're increasing it to 5.6% per annum. 🙂 No annual fee, and no fees for anything else for that matter.
My funds are transferred from my ING account to my "regular bank acount" by the next business day if I transfer before 4pm the day before. I've never had a problem with running out of funds in my "regular" bank account because I always leave $100 in that account. This gives me around 1 day where I only have access to $100 in my bank and the money currently in my wallet (usually $200). I can live with only $300 for 24 hours, along with my credit card (nothing owing on it), and an account I have in Canada.
In Canada, I use PC Financial because I have a high interest savings account (of only 3.05%), chequing account (free cheques!!), and credit card is also with them (easy to pay the cc bill), and it seems easier than ING.