I successfully grew a 4-stem espalier gardener's delight tomato plant upside down and it successfully grew and ripened 23 trusses of fruit, which is a huge haul for a home gardener in the UK.
The supporting frame was of bamboo, three upright 6ft canes, one in the middle, one each 6 ft either side, 6x 8ft laterals, tied together in two layers, 2ft apart, at 2ft 6" and 4ft 6", with a width either side of ~ 12 ft.
I made the contraption myself from a 20 litre chicken manure bucket, with a number of small holes in the bottom and sides, for root breathing and drainage, and a 38mm (1.5") hole for the plant stem, hung on a hanging basket bracket, so there were no issues of breakage.
The plants obviously do try to turn to reach for the Sun, I would have though that obvious, but were trained on the espalier frame.
Gardener's Delight is an heirloom tomato, slightly bigger than cherry, nearly golf-ball size.
There are obvious benefits to this method:
1) Escape soil diseases and pests, like alternaria, fusarium, verticillium, slugs, nematodes etc.
2) Flowers or other crops, like lettuce can be grown on top.
3) Drainage is slower than in "right-way-up" buckets.
The main disadvantages are:
1)They are still a lot of work, they may drain slower than other buckets, but they still drain far more quickly than the ground, and need a lot of tying in.
2) They get heavy and are difficult to move out of adverse weather.
3) You can't grow big tomatoes without some kind of frame, as it's difficult to support heavy trusses, which have the potential to break the vine.
One other major difference is, if you over-water, then instead of killing the roots, you'll rot the stem, as it drains, which is what may have happened to Mrsclem's tomatoes, as she wrote "They require a lot of fertilizer and almost constant watering"
en.wikipedia.org
I have a couple more of those Topsy Turvy things, I bought them for only a dollar each, but I don't think they were even worth that. I'll send them to Goodwill. 
