Unfortunately, there's only one brand available in my city, and that's Guayaki, so I wouldn't know any other brand to recommend. All Yerba Mate kind of tastes burnt, though. You may want to try steeping it for less time than is recommended if it's too bitter.

My favorite way to drink it is sweetened with some sugar and then 5 or 6 drops of lemon juice added. It completely changes the flavor. Several of my non-tea-drinking friends love it when I prepare it like this.

It all tastes pretty bad at first, but Adagio has some interesting blends that might make it easy to ease into mate.

http://www.adagio.com/herbal/mate_sampler.html