I laugh at the reasons the commercials give us for planting our tomatoes upside down. "The water gets to the roots!" Well yeah, it does that when they are upright too. "Gravity draws the water and nutrients to the fruit!" Umm, I don't think that's how it works. "Planting a garden is back-breaking work!" Yeah, so is trying to hang up a 70-pound bag of dirt. "Garden tomatoes can fall to the ground and spoil!" They can if they are growing upside-down too, moron. "Now you can enjoy fresh tomatoes all season long!" You can do that if you plant them in the ground too.
The main appeal of something like this is that it is novel and cool. I thought of making one with a 3-liter soda bottle for the sake of having something interesting to pique the neighbors' interest, but ended up not getting around to it. It would be especially neat to plant the tomatoes hanging from the bottom, and then use the dirt on top to grow herbs! But it's not something worth paying $20 for. If you need to grow tomatoes in commercial dirt away from weeds and pests, then just buy a $4 planter at a discount store and plant them upright.
Several of my neighbors have upside-down planters. They planted their tomatoes around the same time I planted mine in my garden. My Romas have full-sized green tomatoes now that only need to get red. My heirlooms all have small green tomatoes on them. My neighbors have NO tomatoes thus far. And one of them had a plant that grew upward until it got too heavy and broke off.
--S.