My guess is the cancer link has more to do with the way people drink it than the beverage itself. First of all, if you're drinking any hot drink, waiting until it cools a bit is just common sense. And drinking a hot beverage through a straw is just stupid. If you have ever slurped anything hot through a straw, you know it burns you much easier.
Anyway, I make it in a french press, let it cool until it's just warm and drink it. I bought this press at Wal Mart for $12. Originally, I didn't even use it. I just wanted to try it for a few cups of coffee. I started using it for mate when I realized it was just practical. It's a cheap one though and has rusted quite a bit. I recommend you buy a good one in the first place if you're going to use this method.
I noticed the effect far more when I first started drinking it than I do drinking it on a daily basis. But I think there's probably a lot to be said for drinking it in relatively small quantities. I've drunk as much as 25 ounces at a time and did not notice any proportional boost in the good effects while I did notice an awful unpleasant head buzz. Not to mention the effects from the tannins. They're not nearly as strong as in black tea but it does have some and they will upset your stomach if you're sensitive to them.
I recommend looking for a brand that doesn't have too much dust to start out with and see how you do. I'm drinking Rosamonte at the moment but don't really care for the dust. Guayaki is widely available where I live but it's too expensive (IMO) to drink daily.
Anyway, the effects are subtle but if you drink it for a while and then suddenly stop, you will notice that you feel down and it will pick you back up when you have some again. The only thing is you might have to order it if you want to choose your brand. There are only one or two brands I know of that are available to buy here locally. A pity. This stuff is good enough that America should be more aware of it.