I use sweetleaf liquid drops and stevita granulated.
the sweetleaf drops do lend a weird taste/after taste at first but you get used to it after awhile. I dont use the regular drops though I always go for the vanilla cream. the regular sweetleaf is really not good.
stevita is awesome though. 1 packet is perfect for 16 oz. of liquid so have a packet for a standard cup of tea or coffee works very well.
I've been using stevia since you had to buy it as a green powder in the "supplement" section of the local hippy store because 1) the FDA hadn't yet approved it as a sweetener and 2) Whole Foods hadn't taken over the world yet. I wish I could remember the name of the place I used to go to in Fair Oaks, CA. That place was cool but I'm sure it's since been bought by or run out of business by Whole Foods.
Pardon my walk down memory lane. I currently like the Whole Foods brand liquid extract. Sweetleaf is good too.