If your yard looks like a giant salad bowl filled with dandelion greens than there is no single weeding tool that is going to help you take back your lawn. To remove the problem you must remove the cause and in this case it is the soil.
I have owned several homes and had to start a new lawn four times. Inheriting a lawn full of weeds is equally frustrating but it is a winnable war. The lawn in the picture below is not my lawn but my lawn did look a lot like it 3 years ago.
So how did I do it? For starters I used a preemergent crabgrass herbicide to reduce that portion of my problem. Then I started to apply weed & feed as directed. I aerated twice a year and then reduced the amount of herbicide use to just spot applications. I used the Weed Zinger, and about 7 different weeding devices for a fair comparison, and I would spend literally hours weeding with my family...children mostly because they love it.
Today my 2 acre yard looks like a park and I rarely find a dandelion of any size. I still have a few spots where annual blue grass appears and I allow the clover to exist but only in moderation due to the positve impact it has replenishing the nutrients. Pictured below is what a section of my yard looks like now. The entire yard looks like this and I have not used the weeding tool in over 2 months. That is how you win the war on weeds. You don't purchase a weeding tool, work it for a few hours, get frustrated and toss it away or return it. The Scotts commercial truly has the correct approach "just feed it".
By the way the two small circles in the left foreground are not weeds they arepopped balloons from a birthday party.