This  year I tried 6 grafted tomatoes alongside six nongrafted, three varietys of each. The experiment now seems conclusive, in a polytunnel slightly higher yields of all grafted, but i enjoyed the flavour of the non grafted much more! Perhaps I just like gardeners delight, shirly, and sungold more than the three grafted. In no way can Ijustify the heavy outlay on the grafted plants as the results for a small vocational garden barely show any benefit.