What is the hardiest tomato that you have grown?
For me it is Juliet -- the "sort of" paste/grape tomato. It grows the longest, and is the most (foliage) disease resistant tomato that I've grown, year after year. Certainly not the best tasting, but versatile and dependable, and still producing well when others are gone or producing badly cracked fruit.
New to me this year, but also proved very hardy -- Momotoro.
Another long-producer -- Burpee's "Big Mama."