It does not taste 100% like sugar but most of the "aftertaste" some folks complain about come from the cheaper brands use of additives to "stretch" the powder or preservatives like alcohol that some add so you don't have to refrigerate it. Sweet Drops is the only brand I've found that is just stevia and water and it has to be refrigerated after you open it. Stevia is a powerful sweetener so you have to be judicious using it.
Also I've found tha the taste difference is more pronounced in hot coffee. In iced coffee, tea, or anything citrus like lemonade it is a PERFECT sweetener with no aftertaste.
One last one. I don't like plain water but I LOVE juices. Unfortunately as a diabetic they are tough on my sugar levels so now I take my big Yeti tumbler and make a mix of 1/5 juice and water and sweeten with stevia and it is delicious and low in calories. I drink a couple of those every day. Orange juice works great! So does Welch's 100% real grape juice and tart cherry juice is another big favorite! But I've tried it with mango, pineapple, guava and others and it works with all of the.
I also carry that Yeti around the house with me and sip on it all day. I also now put it in my Takeya (Google them) big insulated steel water bottles when I leave the house and have it with me wherever I go. Much better that carrying around plastic water bottles (and cheaper than buying those when I'm out and about) and my drinks stay cold even inside a hot car.