So far it seems to be working well.
I didn't invest in the box of plastic baling twine, but I will -- a single role of string isn't quite enough. Of course 9,000' or so of baling twine that comes in a box will be a lifetime supply. They come in a box of two rolls, since most balers use two strings. I would use the plastic, the sisal (natural fiber) I believe will stretch too much over the season. It should last several seasons if you pick it up at the end of the season -- might have to tie in a little extra from time to time to make up for what you lose cutting the knots each year. The twine will be about $25-30 depending on the sale prices.
Here's a big view. Lettuce is interplanted in parts of the rows.
Now let's look at a close up of one of the plants. I'm pruning my tomatoes this year -- everything below the level of the first flowers. It's supposed to improve the quality, as well as reduce the risk of diseases being picked up from the soil / humidity near the ground.
The little knots use short pieces of string to tie the lateral strings together. It really strengthens them. I tie them where it's convienent then slide it over to where they support the plant well.If the my early optimism proves accurate, I'll expand this to do all my tomatoes next year and not use the cages for them.